Daily Current Affairs – SARKARI LIBRARY

Polygon|MATHS

एक नियमित बहुभुज का प्रत्येक आंतरिक कोण 150° है। उसकी भुजाओं की संख्या कितनी है?

Explanation:

12 सही उत्तर है। बाह्य कोण = 180° − 150° = 30°। भुजाओं की संख्या = 360°/30° = 12।
8 भुजाओं वाले बहुभुज का प्रत्येक आंतरिक कोण 135° होता है।
10 भुजाओं वाले बहुभुज का प्रत्येक आंतरिक कोण 144° होता है।
15 भुजाओं वाले बहुभुज का प्रत्येक आंतरिक कोण 156° होता है।

एक नियमित बहुभुज के आंतरिक कोणों का योग 1260° है। इसमें कितनी भुजाएँ हैं?

Explanation:

9 सही उत्तर है। आंतरिक कोणों का योग = (n−2) × 180°। अतः (n−2) × 180° = 1260° ⇒ n−2 = 7 ⇒ n = 9।
7 भुजाओं के लिए योग 900° होगा।
8 भुजाओं के लिए योग 1080° होगा।
10 भुजाओं के लिए योग 1440° होगा।

एक नियमित बहुभुज का प्रत्येक आंतरिक कोण 135° है। वह कौन-सा बहुभुज है?

Hexagon
Heptagon
Octagon
Nonagon

Explanation:

Octagon सही उत्तर है। बाह्य कोण = 180° − 135° = 45°। अतः भुजाओं की संख्या = 360°/45° = 8। 8 भुजाओं वाले बहुभुज को Octagon कहते हैं।
Hexagon में 6 भुजाएँ होती हैं।
Heptagon में 7 भुजाएँ होती हैं।
Nonagon में 9 भुजाएँ होती हैं।

एक नियमित बहुभुज का प्रत्येक बाह्य कोण 30° है। उसकी भुजाओं की संख्या है:

Explanation:

12 सही उत्तर है। नियमित बहुभुज में बाह्य कोण = 360°/n। अतः n = 360°/30° = 12।
10 भुजाओं के लिए बाह्य कोण 36° होगा।
15 भुजाओं के लिए बाह्य कोण 24° होगा।
18 भुजाओं के लिए बाह्य कोण 20° होगा।

किसी नियमित बहुभुज की प्रत्येक बाह्य कोण 24° है। उसका प्रत्येक आंतरिक कोण कितना होगा?

144°
150°
156°
160°

Explanation:

156° सही उत्तर है। आंतरिक कोण + बाह्य कोण = 180°। अतः आंतरिक कोण = 180° − 24° = 156°।
144° के लिए बाह्य कोण 36° होगा।
150° के लिए बाह्य कोण 30° होगा।
160° के लिए बाह्य कोण 20° होगा।

एक नियमित बहुभुज की भुजाओं की संख्या 18 है। प्रत्येक बाह्य कोण होगा:

15°
18°
20°
24°

Explanation:

20° सही उत्तर है। प्रत्येक बाह्य कोण = 360°/n = 360°/18 = 20°।
15° 24 भुजाओं वाले बहुभुज का बाह्य कोण होगा।
18° 20 भुजाओं वाले बहुभुज का बाह्य कोण होगा।
24° 15 भुजाओं वाले बहुभुज का बाह्य कोण होगा।

एक नियमित बहुभुज के प्रत्येक आंतरिक और बाह्य कोण का अनुपात 5:1 है। बहुभुज की भुजाएँ कितनी हैं?

Explanation:

12 सही उत्तर है। आंतरिक कोण : बाह्य कोण = 5:1। दोनों का योग 180° है। कुल 6 भाग = 180°, इसलिए बाह्य कोण = 30°। अतः n = 360°/30° = 12।
8 भुजाओं वाले बहुभुज में अनुपात 3:1 होता है।
10 भुजाओं वाले बहुभुज में अनुपात 4:1 होता है।
15 भुजाओं वाले बहुभुज में अनुपात 6.5:1 होता है।

किसी नियमित बहुभुज में आंतरिक कोण : बाह्य कोण = 7:2 है। उसकी भुजाओं की संख्या ज्ञात कीजिए।

Explanation:

9 सही उत्तर है। दोनों कोणों का योग 180° है। कुल भाग = 7+2 = 9। प्रत्येक भाग = 20°। बाह्य कोण = 2×20° = 40°। अतः n = 360°/40° = 9।
7 भुजाओं के लिए बाह्य कोण लगभग 51.43° होता है।
11 भुजाओं के लिए बाह्य कोण लगभग 32.73° होता है।
12 भुजाओं के लिए बाह्य कोण 30° होता है।

किसी नियमित बहुभुज के आंतरिक कोण और बाह्य कोण का अनुपात 4:1 है। प्रत्येक आंतरिक कोण होगा:

120°
135°
144°
150°

Explanation:

144° सही उत्तर है। अनुपात 4:1 है और दोनों का योग 180° है। कुल 5 भाग = 180° ⇒ 1 भाग = 36°। आंतरिक कोण = 4×36° = 144°।
120° के लिए बाह्य कोण 60° होगा।
135° के लिए बाह्य कोण 45° होगा।
150° के लिए बाह्य कोण 30° होगा।

एक polygon में 20 diagonals हैं। उसकी भुजाओं की संख्या कितनी है?

Explanation:

8 सही उत्तर है। Diagonals = n(n−3)/2। अतः 20 = n(n−3)/2 ⇒ n(n−3) = 40। n = 8 होने पर 8×5/2 = 20।
7 भुजाओं में 14 diagonals होते हैं।
9 भुजाओं में 27 diagonals होते हैं।
10 भुजाओं में 35 diagonals होते हैं।

एक polygon में 35 diagonals हैं। वह polygon है:

Octagon
Nonagon
Decagon
Dodecagon

Explanation:

Decagon सही उत्तर है। 10 भुजाओं वाले polygon के diagonals = 10×(10−3)/2 = 35। इसलिए polygon Decagon है।
Octagon में 20 diagonals होते हैं।
Nonagon में 27 diagonals होते हैं।
Dodecagon में 54 diagonals होते हैं।

एक polygon के एक vertex से 7 diagonals खींचे जा सकते हैं। polygon की sides कितनी हैं?

Explanation:

10 सही उत्तर है। एक vertex से diagonals की संख्या = n−3। अतः n−3 = 7 ⇒ n = 10।
8 भुजाओं से एक vertex से 5 diagonals बनेंगे।
9 भुजाओं से एक vertex से 6 diagonals बनेंगे।
11 भुजाओं से एक vertex से 8 diagonals बनेंगे।

एक regular polygon की प्रत्येक exterior angle 45° है। उसके interior angles का कुल योग कितना होगा?

900°
1080°
1260°
1440°

Explanation:

1080° सही उत्तर है। n = 360°/45° = 8। आंतरिक कोणों का योग = (8−2)×180° = 1080°।
900° 7 भुजाओं वाले polygon के लिए होगा।
1260° 9 भुजाओं वाले polygon के लिए होगा।
1440° 10 भुजाओं वाले polygon के लिए होगा।

किसी regular polygon में प्रत्येक interior angle, प्रत्येक exterior angle से 120° अधिक है। polygon की sides कितनी हैं?

Explanation:

8 सही उत्तर है। मान लें बाह्य कोण = x। तब आंतरिक कोण = x+120°। दोनों का योग 180° ⇒ 2x+120° = 180° ⇒ x = 30°। अतः n = 360°/30° = 12। इसलिए दिए गए विकल्पों में कोई सही उत्तर नहीं है।
सही भुजाओं की संख्या 12 है, जो विकल्पों में उपलब्ध नहीं है।
इस प्रश्न के विकल्पों में सुधार आवश्यक है।

किसी polygon के interior angles का sum उसके exterior angles के sum का 4 गुना है। polygon की sides कितनी हैं?

Explanation:

10 सही उत्तर है। Exterior angles का योग = 360°। Interior angles का योग = 4×360° = 1440°। अतः (n−2)×180° = 1440° ⇒ n−2 = 8 ⇒ n = 10।
8 भुजाओं के लिए interior angle sum 1080° होगा।
12 भुजाओं के लिए interior angle sum 1800° होगा।

निम्न में से कौन-सा कथन सही है?

केवल 1
केवल 1 और 2
केवल 2 और 3
1, 2 और 3

Explanation:

1, 2 और 3 सही उत्तर है। किसी भी polygon के exterior angles का sum 360° होता है। Regular polygon में सभी exterior angles बराबर होते हैं। तथा n-sided polygon में diagonals = n(n−3)/2 होते हैं।
कथन 1 सही है।
कथन 2 सही है।
कथन 3 भी सही है। इसलिए सभी कथन सही हैं।

किसी n-sided polygon को उसके एक vertex से कितने triangles में विभाजित किया जा सकता है?

n−1
n−2
n−3
2n−3

Explanation:

n−2 सही उत्तर है। किसी n-sided polygon को एक vertex से diagonals खींचकर n−2 triangles में विभाजित किया जा सकता है।
n−1 triangles की संख्या नहीं होती।
n−3 एक vertex से खींचे जा सकने वाले diagonals की संख्या है।

एक regular polygon में प्रत्येक interior angle, exterior angle का 8 गुना है। polygon की sides कितनी हैं?

Explanation:

20 सही उत्तर है। मान लें बाह्य कोण = x। आंतरिक कोण = 8x। दोनों का योग 180° ⇒ 9x = 180° ⇒ x = 20°। अतः n = 360°/20° = 18। इसलिए सही उत्तर 18 है।
16 भुजाओं वाले polygon का बाह्य कोण 22.5° होगा।
20 भुजाओं वाले polygon का बाह्य कोण 18° होगा।
24 भुजाओं वाले polygon का बाह्य कोण 15° होगा।

किसी polygon में diagonals की संख्या उसकी sides की संख्या से 5 गुना है। polygon की sides कितनी हैं?

Explanation:

10 सही उत्तर है। n(n−3)/2 = 5n। n ≠ 0 होने पर (n−3)/2 = 5 ⇒ n−3 = 10 ⇒ n = 13। इसलिए सही उत्तर 13 है।
8 भुजाओं में 20 diagonals होते हैं, जो sides के 2.5 गुना हैं।
10 भुजाओं में 35 diagonals होते हैं।
12 भुजाओं में 54 diagonals होते हैं।

एक regular polygon की प्रत्येक interior angle 160° है। उसके diagonals की संख्या कितनी होगी?

90
100
104
105

Explanation:

105 सही उत्तर है। बाह्य कोण = 180°−160° = 20°। अतः n = 360°/20° = 18। Diagonals = 18×(18−3)/2 = 18×15/2 = 135। इसलिए दिए गए विकल्पों में कोई सही उत्तर नहीं है।
18 भुजाओं वाले polygon में 135 diagonals होते हैं।
105 diagonals 15 भुजाओं वाले polygon में होते हैं।
इस प्रश्न के options में सुधार आवश्यक है।

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Tourism Incentive Portal
Startup Incentive Portal
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Explanation:

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राजनाथ सिंह
नितिन गडकरी
अश्विनी वैष्णव
पीयूष गोयल

Explanation:

नितिन गडकरी ने गुजरात के एकता नगर में Chintan Shivir 2026 का उद्घाटन किया।
इसका motto “Gatishakti se Pragati” है।

MOUNTAIN GUARDIAN 2026 भारत और किस देश के बीच संयुक्त सैन्य अभ्यास है?

भारत और फ्रांस
भारत और जापान
भारत और UAE
भारत और अमेरिका

Explanation:

MOUNTAIN GUARDIAN 2026 भारत और UAE के बीच संयुक्त सैन्य अभ्यास है।
यह 5 से 18 अक्टूबर 2026 तक उत्तराखंड के चौबटिया में आयोजित किया जा रहा है।
अभ्यास का मुख्य फोकस पर्वतीय युद्ध (Mountain Warfare) है।

CURRENT-AFFAIRS

भारत की ‘अमरूद राजधानी’ (Guava Capital) के नाम से किस शहर को जाना जाता है?

लखनऊ
प्रयागराज
वाराणसी
कानपुर

Explanation:

प्रयागराज को भारत की ‘अमरूद राजधानी’ (Guava Capital) के नाम से जाना जाता है।
यह उत्तर प्रदेश में स्थित है।

उत्तर प्रदेश के भदोही का नया नाम क्या है?

संत कबीर नगर भदोही
संत रविदास नगर भदोही
रविदास नगर प्रयागराज
संत रविदास नगर वाराणसी

Explanation:

उत्तर प्रदेश के भदोही का नाम बदलकर संत रविदास नगर भदोही किया गया है।

2030 के 21वें एशियाई खेलों की मेजबानी कौन करेगा?

जापान
चीन
कतर
दक्षिण कोरिया

Explanation:

कतर 2030 में 21वें एशियाई खेलों की मेजबानी करेगा।
एशियाई खेलों का आयोजन दोहा में किया जाएगा।
दोहा 2030 का आदर्श वाक्य “The Games We Live For” है।

वर्ष 2026 का नोबेल पुरस्कार (Physiology or Medicine) किन्हें संयुक्त रूप से दिया गया?

Karl Deisseroth, Peter Hegemann और Georg Nagel
David Baker, Demis Hassabis और John Jumper
Victor Ambros और Gary Ruvkun
Katalin Karikó और Drew Weissman

Explanation:

Karl Deisseroth, Peter Hegemann और Georg Nagel को 2026 का नोबेल पुरस्कार (Physiology or Medicine) संयुक्त रूप से दिया गया।
उन्हें प्रकाश-सक्रिय आयन चैनल और Optogenetics से संबंधित खोजों के लिए सम्मानित किया गया।

World Architecture Day 2026 की थीम क्या है?

Architecture for All
Housing is a Human Right. Build It.
Building a Better Future
Sustainable Cities for All

Explanation:

World Architecture Day 2026 की थीम “Housing is a Human Right. Build It.” है।
यह थीम International Union of Architects (UIA) द्वारा दी गई है।
World Architecture Day 2026 को 5 अक्टूबर 2026 को मनाया गया।

19वाँ प्रवासी भारतीय दिवस सम्मेलन 2027 में कहाँ आयोजित किया जाएगा?

नई दिल्ली
मुंबई
कोलकाता
अहमदाबाद

Explanation:

19वाँ प्रवासी भारतीय दिवस सम्मेलन 7 से 9 जनवरी 2027 तक कोलकाता में आयोजित किया जाएगा।

भारत ने पहला Free-Space Quantum Key Distribution (QKD) लिंक कितनी दूरी का प्रदर्शित किया?

2.56 किमी
5.56 किमी
10.56 किमी
15.56 किमी

Explanation:

भारत ने 5.56 किमी का पहला Free-Space Quantum Key Distribution (QKD) लिंक प्रदर्शित किया।
इसमें QNu Labs की QKD तकनीक और BISAG-N का Post-Quantum Cryptography प्लेटफॉर्म शामिल था।

World Habitat Day 2026 की थीम क्या है?

Housing for Everyone
Adequate Housing for All
Better Cities, Better Life
Housing and Sustainable Development

Explanation:

World Habitat Day 2026 को 5 अक्टूबर 2026 को मनाया गया।
वर्ष 2026 की थीम “Adequate Housing for All” है।

World Teachers’ Day 2026 की थीम क्या है?

Teachers at the Heart of Education
Empowering Teachers for the Future
Standing with teachers: 60 years of protecting the profession, advancing its status and shaping our futures
Teachers Build the Nation

Explanation:

World Teachers’ Day प्रत्येक वर्ष 5 अक्टूबर को मनाया जाता है।
वर्ष 2026 की थीम “Standing with teachers: 60 years of protecting the profession, advancing its status and shaping our futures” है।
2026 में 1966 के ILO-UNESCO Recommendation concerning the Status of Teachers के 60 वर्ष पूरे हुए हैं।

CURRENT-AFFAIRS

भारत का पहला प्लास्टिक-मुक्त तेल टर्मिनल किसे बनाया गया है?

मुंबई पोर्ट
जवाहर द्वीप, मुंबई
कांडला पोर्ट
कोच्चि पोर्ट

आंध्र प्रदेश के मदनपल्ले में शुरू किए गए Global Horticulture Hub में कितने जिले और कितने क्लस्टर शामिल हैं?

8 जिले, 150 क्लस्टर
10 जिले, 201 क्लस्टर
12 जिले, 250 क्लस्टर
15 जिले, 300 क्लस्टर

15 वर्ष की उम्र में TIME100 Next 2026 के सबसे युवा सम्मानित व्यक्ति कौन बने?

प्रणवी उर्स
कुमकुम मोहोड
वैभव सूर्यवंशी
Oh Yejin

COP31 (UNFCCC) का आयोजन कहाँ किया जाएगा?

नई दिल्ली
पेरिस
अंताल्या
दुबई

विश्व पशु दिवस प्रत्येक वर्ष कब मनाया जाता है?

2 अक्टूबर
4 अक्टूबर
5 अक्टूबर
10 अक्टूबर

Asian Games 2026 के पुरुष क्रिकेट फाइनल में भारत ने किस देश को हराकर स्वर्ण पदक जीता?

श्रीलंका
बांग्लादेश
पाकिस्तान
चीन

Asian Games 2026 में स्वर्ण पदक जीतने वाली पहली भारतीय महिला गोल्फर कौन बनीं?

अदिति अशोक
प्रणवी उर्स
वाणी कपूर
दीक्षा डागर

Asian Games 2026 में महिला व्यक्तिगत रिकर्व का स्वर्ण पदक किस भारतीय तीरंदाज ने जीता?

दीपिका कुमारी
ज्योति सुरेखा वेन्नम
कुमकुम मोहोड
अंकिता भकत

Asian Games 2026 की पदक तालिका में सर्वाधिक कुल पदक किस देश ने जीते?

जापान
भारत
दक्षिण कोरिया
चीन

Asian Games 2026 की पदक तालिका में चीन ने कुल कितने पदक जीते?

269
150
85
341

Asian Games 2026 की पदक तालिका में जापान का स्थान और कुल पदकों की संख्या क्या रही?

प्रथम, 341 पदक
द्वितीय, 269 पदक
तृतीय, 150 पदक
चतुर्थ, 85 पदक

Asian Games 2026 की पदक तालिका में भारत का स्थान और कुल पदकों की संख्या क्या रही?

द्वितीय, 269 पदक
तृतीय, 150 पदक
चतुर्थ, 85 पदक
पंचम, 75 पदक

Asian Games 2026 में भारत ने कुल कितने स्वर्ण, रजत और कांस्य पदक जीते?

19 स्वर्ण, 27 रजत, 39 कांस्य
21 स्वर्ण, 27 रजत, 37 कांस्य
21 स्वर्ण, 37 रजत, 27 कांस्य
27 स्वर्ण, 21 रजत, 37 कांस्य

Asian Games 2026 में चीन ने कितने स्वर्ण पदक जीते?

83
89
169
341

Asian Games 2026 में भारत ने कितने स्वर्ण पदक जीते?

जवाहर द्वीप, मुंबई: भारत का पहला प्लास्टिक-मुक्त तेल टर्मिनल बना।
आंध्र प्रदेश: मदनपल्ले में ₹1 लाख करोड़ का Global Horticulture Hub शुरू; 10 जिले, 201 क्लस्टर।
वैभव सूर्यवंशी: 15 वर्ष की उम्र में TIME100 Next 2026 के सबसे युवा सम्मानित व्यक्ति बने।
COP31 (UNFCCC) : 9–20 नवंबर 2026, अंताल्या, तुर्किये में आयोजित होगा।
विश्व पशु दिवस: हर वर्ष 4 अक्टूबर को मनाया जाता है।
Asian Games 2026
- भारत (211/6) ने पुरुष क्रिकेट फाइनल में पाकिस्तान को हराकर स्वर्ण पदक जीता।
- प्रणवी उर्स: एशियन गेम्स 2026 में स्वर्ण जीतने वाली पहली भारतीय महिला गोल्फर बनीं।
- कुमकुम मोहोड: 17 वर्षीय भारतीय तीरंदाज ने शूट-ऑफ में दक्षिण कोरिया की Oh Yejin को हराकर महिला व्यक्तिगत रिकर्व स्वर्ण जीता और LA28 कोटा हासिल किया।

रैंक	देश	स्वर्ण 🥇	रजत 🥈	कांस्य 🥉	कुल पदक
1	चीन	169	89	83	341
2	जापान	83	95	91	269
3	दक्षिण कोरिया	39	43	68	150
4	भारत 🇮🇳	21	27	37	85

CURRENT-AFFAIRS

HDFC Bank के MD एवं CEO के रूप में किसे नियुक्त किया गया है?

अनूप बागची
Sashidhar Jagdishan
अशोक वासवानी
शशांक श्रीवास्तव

Explanation:

अनूप बागची को HDFC Bank का MD एवं CEO नियुक्त किया गया है।
उनका कार्यकाल 27 अक्टूबर 2026 से 3 वर्ष का होगा।
वे वर्तमान MD एवं CEO Sashidhar Jagdishan का स्थान लेंगे।

‘Vettri Payanam’ योजना किस राज्य से संबंधित है?

केरल
तमिलनाडु
कर्नाटक
आंध्र प्रदेश

Explanation:

तमिलनाडु के मुख्यमंत्री C. Joseph Vijay ने 2 अक्टूबर 2026 को ‘Vettri Payanam’ नामक विस्तारित मुफ्त सरकारी बस यात्रा योजना शुरू की।
इस योजना की शुरुआत कोयम्बेडु बस टर्मिनस, चेन्नई से की गई।

ICC पुरुष क्रिकेट विश्व कप 2027 का आयोजन कब से कब तक होगा?

1 जनवरी–31 जनवरी 2027
2 अक्टूबर–21 नवंबर 2027
15 सितंबर–15 नवंबर 2027
1 अक्टूबर–30 नवंबर 2027

Explanation:

ICC पुरुष क्रिकेट विश्व कप 2027 का आयोजन 2 अक्टूबर से 21 नवंबर 2027 तक होगा।
इसके सह-मेजबान दक्षिण अफ्रीका, जिम्बाब्वे और नामीबिया हैं।

अंतरराष्ट्रीय अहिंसा दिवस कब मनाया जाता है?

15 अगस्त
2 अक्टूबर
5 सितंबर
14 नवंबर

Explanation:

अंतरराष्ट्रीय अहिंसा दिवस प्रत्येक वर्ष 2 अक्टूबर को मनाया जाता है।
यह दिन महात्मा गांधी की जयंती के अवसर पर मनाया जाता है।

वर्ष 2026 में लाल बहादुर शास्त्री की कौन-सी जयंती मनाई गई?

120वीं
121वीं
122वीं
123वीं

Explanation:

लाल बहादुर शास्त्री जयंती प्रत्येक वर्ष 2 अक्टूबर को मनाई जाती है।
वर्ष 2026 में उनकी 122वीं जयंती मनाई गई।
लाल बहादुर शास्त्री भारत के पूर्व प्रधानमंत्री थे।

Asian Games 2026 में महिला रिकर्व आर्चरी टीम में भारत ने किस पदक को जीता?

स्वर्ण पदक
रजत पदक
कांस्य पदक
कोई पदक नहीं

Explanation:

अंकिता भाकत, कीर्ति शर्मा और कुमकुम मोहद ने महिला रिकर्व आर्चरी टीम स्पर्धा में स्वर्ण पदक जीता।

Asian Games 2026 में महिला 75 किग्रा मुक्केबाजी में स्वर्ण पदक किसने जीता?

लवलीना बोरगोहेन
परवीन हुडा
अंकिता भाकत
नेत्रा कुमानन

Explanation:

लवलीना बोरगोहेन ने महिला 75 किग्रा मुक्केबाजी में स्वर्ण पदक जीता।

Asian Games 2026 में महिला 65 किग्रा मुक्केबाजी में स्वर्ण पदक किसने जीता?

लवलीना बोरगोहेन
परवीन हुडा
कुमकुम मोहद
अंकिता भाकत

Explanation:

परवीन हुडा ने महिला 65 किग्रा मुक्केबाजी में स्वर्ण पदक जीता।

Asian Games 2026 में पुरुष 80 किग्रा मुक्केबाजी में स्वर्ण पदक किसने जीता?

अंकुश पांघल
धीरज बोम्मदेवरा
सुजीत कल्कल
यशदीप भोग

Explanation:

अंकुश पांघल ने पुरुष 80 किग्रा मुक्केबाजी में स्वर्ण पदक जीता।

Asian Games 2026 में भारतीय महिला हॉकी टीम ने कौन-सा पदक जीता?

स्वर्ण पदक
रजत पदक
कांस्य पदक
कोई पदक नहीं

Explanation:

भारतीय महिला हॉकी टीम ने Asian Games 2026 में स्वर्ण पदक जीता।

Asian Games 2026 में पुरुष फ्रीस्टाइल 65 किग्रा कुश्ती में स्वर्ण पदक किसने जीता?

सुजीत कल्कल
अंकुश पांघल
धीरज बोम्मदेवरा
नीरज चौहान

Explanation:

सुजीत कल्कल ने पुरुष फ्रीस्टाइल 65 किग्रा कुश्ती में स्वर्ण पदक जीता।

Asian Games 2026 में मिश्रित रिकर्व टीम में रजत पदक जीतने वाले भारतीय खिलाड़ियों में कौन शामिल हैं?

कुमकुम मोहद और धीरज बोम्मदेवरा
अंकिता भाकत और सुजीत कल्कल
लवलीना बोरगोहेन और परवीन हुडा
नेत्रा कुमानन और अंकुश पांघल

Explanation:

कुमकुम मोहद और धीरज बोम्मदेवरा ने मिश्रित रिकर्व टीम स्पर्धा में रजत पदक जीता।

Asian Games 2026 में पुरुष रिकर्व टीम ने कौन-सा पदक जीता?

स्वर्ण पदक
रजत पदक
कांस्य पदक
कोई पदक नहीं

Explanation:

धीरज बोम्मदेवरा, यशदीप भोग और नीरज चौहान ने पुरुष रिकर्व टीम स्पर्धा में रजत पदक जीता।

Asian Games 2026 में महिला डिंगी सेलिंग में कांस्य पदक किसने जीता?

नेत्रा कुमानन
कुमकुम मोहद
परवीन हुडा
अंकिता भाकत

Explanation:

नेत्रा कुमानन ने महिला डिंगी सेलिंग में कांस्य पदक जीता।

Asian Games 2026 में पुरुष क्वाड्रेंट सेपकटकरा में भारत ने कौन-सा पदक जीता?

स्वर्ण पदक
रजत पदक
कांस्य पदक
कोई पदक नहीं

Explanation:

भारत ने पुरुष क्वाड्रेंट सेपकटकरा स्पर्धा में कांस्य पदक जीता।

Mechanical

A closed vessel made of steel and used for the generation of steam is called a

steam boiler
steam turbine
steam condenser
steam injector

A good steam boiler is one which produces maximum quantity of steam with the given fuel.

Agree
Disagree

The selection of type and size of a steam boiler depends upon

the power required and working pressure
the geographical position of the power house
the fuel and water available
all of the above

In a fire tube boiler, the water is contained inside the tubes which are surrounded by flames and hot gases from outside.

True
False

In water tube boilers, the water passes through the tubes which are surrounded by flames and hot gases.

Yes
No

Which of the following is a fire tube boiler?

Lancashire boiler
Babcock and Wilcox boiler
Yarrow boiler
none of these

Fire tube boilers are limited to a maximum working pressure of

0.17 MN/m²
1.7 MN/m²
17 MN/m²
170 MN/m²

Which of the following is a water tube boiler?

Lancashire boiler
Babcock and Wilcox boiler
Locomotive boiler
Cochran boiler

In fire tube boilers

water passes through the tubes which are surrounded by flames and hot gases
the flames and hot gases pass through the tubes which are surrounded by water
forced circulation takes place
none of these

In water tube boilers

water passes through the tubes which are surrounded by flames and hot gases
the flames and hot gases pass through the tubes which are surrounded by water
forced circulation takes place
none of these

When the circulation of water, in a boiler, is by convection currents which are set up during the heating of water, then the boiler is known as

internally fired boiler
externally fired boiler
natural circulation boiler
forced circulation boiler

When the circulation of water, in a boiler, is by a centrifugal pump, then the boiler is known as

internally fired boiler
externally fired boiler
natural circulation boiler
forced circulation boiler

Fire tube boilers are

internally fired
externally fired
internally as well as externally fired
none of these

Water tube boilers are

internally fired
externally fired
internally as well as externally fired
none of these

Cornish boilers are multi-tubular boilers.

True
False

In natural circulation steam boilers, the circulation of water is by convection currents which are set up during the heating of water.

Right
Wrong

In forced circulation steam boilers, the force is applied

to draw water
to circulate water
to drain off the water
all of these

In a La-mont boiler, there is a …………… circulation of water and steam.

forced
natural

Lancashire boiler is a stationary fire tube boiler.

Agree
Disagree

Water tube boilers produce steam at a …………… pressure than that of fire tube boilers.

lower
higher

The rate of flow of steam is …………… in case of fire tube boilers.

less
more

Which of the following statement is correct?

A fire tube boiler occupies less space than a water tube boiler, for a given power.
Steam at a high pressure and in large quantities can be produced with a simple vertical boiler.
A simple vertical boiler has one fire tube.
all of the above

The water tubes in a simple vertical boiler are

horizontal
vertical
inclined

A Cochran boiler is a horizontal multi-tubular boiler.

The fire tubes in a Cochran boiler usually have …………… diameter.

6.25 mm
62.5 mm
72.5 mm
92.5 mm

The number of fire tubes in a Cochran boiler are

73
115
105
225

A grate, in a boiler, is a place in the combustion chamber upon which fuel (wood or coal) is burnt.

True
False

The shell of the Cochran boiler is made hemispherical

to give maximum space and strength
to withstand the pressure of steam inside the boiler
both (a) and (b)
none of the above

The crown of the fire box is made hemispherical in order to resist intense heat in the fire box.

True
False

The fire tubes in a Cochran boiler are

horizontal
vertical
inclined

A single ended Scotch marine steam boiler may have one to four furnaces which enter from front end of the boiler.

Right
Wrong

The fire tubes in a Scotch marine boiler are

horizontal
vertical
inclined

The diameter of a cylindrical shell of a Scotch marine boiler varies from

1.5 to 2 m
2.5 to 3.5 m
3.5 to 4.5 m
none of these

Lancashire boiler is

stationary fire tube boiler
internally fired boiler
horizontal boiler
all of these

For the same diameter and thickness of tube, a water tube boiler has …………… heating surface as compared to fire tube boiler.

more
less
equal

Lancashire boiler is used where working pressure and power required are

low
moderate
high
none of these

The cylindrical shell of a Lancashire boiler has diameter from

1 to 2 m
1.25 to 2.25 m
1.5 to 2.5 m
1.75 to 2.75 m

The length of Lancashire boiler varies from

5 to 6 m
6 to 7 m
7.25 to 9 m
9 to 10 m

Lancashire boiler has …………… internal flue tubes.

one
two
three
four

The diameter of internal flue tubes of a Lancashire boiler is about …………… that of its shell.

one-fourth
one-third
two-fifth
one-half

The internal flue tubes of a Lancashire boiler are reduced in diameter at the back to provide access to the lower part of the boiler.

True
False

The damper in a steam boiler is provided to control the draught (i.e. rate of flow of air) and thus regulate the rate of generation of steam.

Correct
Incorrect

Which of the following statement indicates the difference between Cornish boiler and Lancashire boiler?

Cornish boiler is a water tube boiler whereas Lancashire boiler is a fire tube boiler.
Cornish boiler is a fire tube boiler whereas Lancashire boiler is a water tube boiler.
Cornish boiler has one flue tube whereas Lancashire boiler has two flue tubes.
Cornish boiler has two flue tubes whereas Lancashire boiler has one flue tube.

The diameter of Cornish boiler varies from

0.5 to 1 m
1 to 2 m
1.25 to 2.5 m
2 to 3 m

The capacity and working pressure of a Cornish boiler is …………… as compared to Lancashire boiler.

low
high

The length of Cornish boiler varies from

2 to 4.5 m
3 to 5 m
5 to 7.5 m
7 to 9 m

The diameter of flue tube in a Cornish boiler is …………… that of the shell.

one-fourth
one-third
two-fifth
three-fifth

Locomotive boiler is a

single tube, horizontal, internally fired and stationary boiler
single tube, vertical, externally fired and stationary boiler
multitubular, horizontal, internally fired and mobile boiler
multitubular, horizontal, externally fired and stationary boiler

Locomotive boiler produces steam at a very high rate.

Yes
No

The shell diameter of a Locomotive boiler is

1 m
1.5 m
2 m
2.5 m

The length of shell of a Locomotive boiler is

1 m
2 m
3 m
4 m

The Locomotive boiler has

137 fire tubes and 44 superheated tubes
147 fire tubes and 34 superheated tubes
157 fire tubes and 24 superheated tubes
167 fire tubes and 14 superheated tubes

The maximum steam pressure in a Locomotive boiler is limited to

0.18 MN/m²
1.8 MN/m²
18 MN/m²
180 MN/m²

The fire tubes in a Locomotive boiler has …………… diameter.

4.75 mm
5.47 mm
7.45 mm
47.5 mm

The diameter of superheated tubes in a locomotive boiler is

13 mm
31 mm
130 mm
230 mm

Locomotive boiler is a …………… boiler.

fire tube
water tube

Babcock and Wilcox boiler is a stationary type of water tube boiler.

Correct
Incorrect

The water tubes in a Babcock and Wilcox boiler are

vertical
horizontal
inclined

The water tube boilers produce steam at a …………… pressure than that of fire tube boilers.

lower
higher

La-mont boiler, is a high pressure water tube steam boiler working on forced circulation.

Agree
Disagree

Which of the following boiler works on a forced circulation of water?

La-mont boiler
Benson boiler
Loefller boiler
all of these

The forced circulation of water does not take place in

La-Mont boiler
Lancashire boiler
Velox boiler
Benson boiler

The working pressure range for a La-Mont boiler is

0.5 to 10 MN/m²
1 to 15 MN/m²
2.5 to 15 MN/m²
3.5 to 20 MN/m²

Loeffler boiler is a water tube boiler using a forced circulation of water.

True
False

Benson boiler requires

no drum
one drum
two drums
three drums

Benson boiler is a …………… water tube steam boiler using forced circulation of water.

low pressure
high pressure

The average operating pressure of Benson boiler is

100 bar
150 bar
200 bar
250 bar

The rate of steam produced in Benson boiler is

100 tonnes/h
135 tonnes/h
175 tonnes/h
250 tonnes/h

Which of the following boiler is best suited to meet the fluctuating demand of steam?

Locomotive boiler
Lancashire boiler
Cornish boiler
Babcock and Wilcox boiler

Which of the following statement is correct?

Lancashire boiler is a fire tube boiler.
Fire tube boilers are internally fired.
Babcock and Wilcox boiler is a water tube boiler.
all of the above

Which of the following statement is wrong?

Locomotive boiler is a water tube boiler.
Water tube boilers are internally fired.
La-mont boiler is a low pressure water tube boiler.
all of the above

The fittings mounted on the boiler for its proper and safe functioning is a

water level indication
pressure gauge
safety valve
all of these

Which of the following is not a boiler mounting?

Blow off cock
Feed check valve
Economiser
Fusible plug

The device attached to the steam chest for preventing explosions due to excessive internal pressure of steam is called

safety valve
water level indicator
pressure gauge
fusible plug

The number of water level indicators in a boiler are generally …………… in number.

one
two
three
four

A water level indicator is a device to indicate the exact water level in the boiler at any instant.

True
False

In a glass tube type water indicator for a boiler, one end of the tube is connected to water space and the other end is connected to

water space also
chimney
steam space
superheater

The function of a safety valve is

to blow off steam when the pressure of steam inside the boiler exceeds the working pressure
to indicate the water level inside the boiler to an observer
to measure pressure of steam inside the steam boiler
none of the above

A safety valve usually employed with stationary boilers is

lever safety valve
dead weight safety valve
high steam and low water safety valve
all of these

A safety valve mainly used with locomotive and marine boilers is

lever safety valve
dead weight safety valve
high steam and low water safety valve
spring loaded safety valve

The high steam and low water safety valve is not used in

Cochran boiler
Cornish boiler
Lancashire boiler
Locomotive boiler

The high steam and low water safety valve is used to blow off steam when the

steam pressure exceeds the working pressure
water level in the boiler becomes too low
both (a) and (b)
none of the above

The principal function of a stop valve is to

control the flow of steam from the boiler to the main pipe and to shut off the steam completely when required
empty the boiler when required and to discharge the mud, scale or sediments which are accumulated at the bottom of the boiler
put off fire in the furnace of the boiler when the level of water in the boiler falls to an unsafe limit
increase the temperature of saturated steam without raising its pressure

Blow off cock in a boiler is used to

control the flow of steam from the boiler to the main pipe and to shut off the steam completely when required
empty the boiler when required and to discharge the mud, scale or sediments which are accumulated at the bottom of the boiler
put off fire in the furnace of the boiler when the level of water in the boiler falls to an unsafe limit
increase the temperature of saturated steam without raising its pressure

A …………… in a boiler is used to put off fire in the furnace of the boiler when the level of water in the boiler falls to an unsafe limit.

blow off cock
fusible plug
stop valve
safety valve

The function of a superheater is to heat the feed water by utilising the heat in the exhaust flue gases before leaving through the chimney.

An economiser is used to increase the temperature of saturated steam without raising its pressure.

Right
Wrong

A device used in a boiler to control the flow of steam from the boiler to the main pipe and to shut off the steam completely when required, is known as

blow off cock
fusible plug
superheater
stop valve

A device used to empty the boiler whenever required and to discharge the mud, scale or sediments which are accumulated at the bottom of the boiler, is called blow off cock.

Yes
No

A valve installed between the boiler and the feed pump is

blow off cock
feed check valve
steam stop valve
none of these

A device used to put off fire in the furnace of the boiler when the level of water in the boiler falls to an unsafe limit, is called

blow off cock
stop valve
superheater
none of these

A device used to increase the temperature of saturated steam without raising its pressure, is called

blow off cock
fusible plug
superheater
stop valve

A device used to heat feed water by utilising the heat in the exhaust flue gases before leaving through the chimney, is known as

economiser
fusible plug
superheater
stop valve

Which of the following are boiler accessories?

economiser
superheater
both (a) and (b)
none of these

An economiser …………… the steam raising capacity of a boiler.

increases
decreases
has no effect on

The pressure of feed water has to be raised before its entry into the boiler. The pressure is raised by a device known as

feed pump
injector
feed check valve
pressure gauge

There is about 15 to 20% of coal saving when an economiser is used in a boiler.

True
False

An economiser is generally placed between

last superheater or reheater and air preheater
induced draft fan and forced draft fan
air preheater and chimney
none of the above

An air preheater

increases evaporative capacity of the boiler
increases the efficiency of the boiler
enables low grade fuel to be burnt
all of the above

An air preheater is installed

before the economiser
before the superheater
between the economiser and chimney
none of these

An economiser is installed in a boiler primarily to

superheat the steam
reduce fuel consumption
increase steam pressure
all of these

A device in which some portion of waste heat of flue gases is recovered to heat the air before it passes to the furnace for combustion purpose, is known as

superheater
air preheater
economiser
injector

CURRENT-AFFAIRS

Flydubai उड़ान घटना के दौरान साहस के लिए 2026 में विशिष्ट गुजरात गरिमा पुरस्कार से किसे सम्मानित किया जाएगा?

नरेंद्र भूषण
रोहित शर्मा
स्मित मच्छर
अनूप कुमार साहा

Explanation:

स्मित मच्छर को Flydubai उड़ान घटना के दौरान साहस के लिए विशिष्ट गुजरात गरिमा पुरस्कार 2026 से सम्मानित किया जाएगा।

अनूप कुमार साहा 1 जनवरी 2027 से किस बैंक के MD एवं CEO बनेंगे?

भारतीय स्टेट बैंक
HDFC बैंक
ICICI बैंक
Kotak Mahindra Bank

Explanation:

अनूप कुमार साहा 1 जनवरी 2027 से तीन वर्ष के लिए Kotak Mahindra Bank के MD एवं CEO बनेंगे।
वे अशोक वासवानी का स्थान लेंगे।
अनूप कुमार साहा का कार्यकाल 1 जनवरी 2027 से शुरू होगा।
उनका कार्यकाल तीन वर्ष का होगा।

किस अमेरिकी राज्य ने AB 1267 के तहत बाल विवाह पर प्रतिबंध लगाया?

न्यूयॉर्क
टेक्सास
फ्लोरिडा
कैलिफोर्निया

Explanation:

कैलिफोर्निया ने AB 1267 के तहत बाल विवाह पर प्रतिबंध लगाया।
इस कानून के तहत न्यूनतम विवाह आयु 18 वर्ष निर्धारित की गई है।

यह कानून 30 सितंबर 2026 से प्रभावी हुआ।

सितंबर 2026 से नरेंद्र भूषण किस मंत्रालय के सचिव बने?

गृह मंत्रालय
वित्त मंत्रालय
पर्यावरण, वन एवं जलवायु परिवर्तन मंत्रालय
कृषि एवं किसान कल्याण मंत्रालय

Explanation:

नरेंद्र भूषण पर्यावरण, वन एवं जलवायु परिवर्तन मंत्रालय (MoEFCC) के सचिव बने।
वे 1992 बैच के UP कैडर के IAS अधिकारी हैं।

30 सितंबर 2026 को गुवाहाटी में वेस्टइंडीज के खिलाफ दूसरे ODI में रोहित शर्मा ने कौन-सा महत्वपूर्ण रिकॉर्ड बनाया?

10,000 ODI रन पूरे किए
11,000 ODI रन पूरे किए
12,000 ODI रन पूरे किए
13,000 ODI रन पूरे किए

Explanation:

रोहित शर्मा ने 30 सितंबर 2026 को गुवाहाटी में वेस्टइंडीज के खिलाफ दूसरे ODI में 12,000 ODI रन पूरे किए।
वे ऐसा करने वाले तीसरे भारतीय बने।
उनसे पहले सचिन तेंदुलकर और विराट कोहली यह उपलब्धि हासिल कर चुके हैं।

Bankers’ Books Evidence Act, 2026 ने किस पुराने अधिनियम का स्थान लिया?

1872 का भारतीय साक्ष्य अधिनियम
1885 का भारतीय टेलीग्राफ अधिनियम
1891 का Bankers’ Books Evidence Act
1908 का सिविल प्रक्रिया अधिनियम

Explanation:

Bankers’ Books Evidence Act, 2026 ने 1891 के अधिनियम का स्थान लिया।
यह बैंकिंग रिकॉर्ड से संबंधित साक्ष्य कानून को आधुनिक बनाता है।
Bankers’ Books Evidence Act, 2026 1 अक्टूबर 2026 से लागू हुआ।
इसने 1891 के पुराने कानून का स्थान लिया।

एशियाई खेल 2026 की 49er नौकायन स्पर्धा में भारत ने कौन-सा पदक जीता?

स्वर्ण पदक
रजत पदक
कांस्य पदक
कोई पदक नहीं

Explanation:

भारत के मनु फ्रांसिस और प्रिंस नोबल ने एशियाई खेल 2026 की 49er नौकायन स्पर्धा में रजत पदक जीता।

एशियाई खेल 2026 में 49er नौकायन स्पर्धा में रजत पदक जीतने वाले भारतीय खिलाड़ी कौन हैं?

अंकिता भक्त और प्रिंस नोबल
मनु फ्रांसिस और प्रिंस नोबल
मनु फ्रांसिस और कीर्ति शर्मा
कुमकुम मोहोड़ और प्रिंस नोबल

Explanation:

मनु फ्रांसिस और प्रिंस नोबल ने 49er नौकायन स्पर्धा में भारत के लिए रजत पदक जीता।

एशियाई खेल 2026 में महिलाओं की टीम रिकर्व स्पर्धा में भारत ने कौन-सा पदक जीता?

रजत पदक
कांस्य पदक
स्वर्ण पदक
कोई पदक नहीं

Explanation:

अंकिता भक्त, कुमकुम मोहोड़ और कीर्ति शर्मा ने तीरंदाजी की महिलाओं की टीम रिकर्व स्पर्धा में स्वर्ण पदक जीता।

एशियाई खेल 2026 की महिलाओं की टीम रिकर्व तीरंदाजी स्पर्धा में स्वर्ण पदक जीतने वाली भारतीय टीम में कौन शामिल थीं?

मनु फ्रांसिस, प्रिंस नोबल और कीर्ति शर्मा
अंकिता भक्त, कुमकुम मोहोड़ और कीर्ति शर्मा
अंकिता भक्त, मनु फ्रांसिस और कुमकुम मोहोड़
कुमकुम मोहोड़, प्रिंस नोबल और कीर्ति शर्मा

Explanation:

भारतीय महिला टीम में अंकिता भक्त, कुमकुम मोहोड़ और कीर्ति शर्मा शामिल थीं।
उन्होंने महिलाओं की टीम रिकर्व स्पर्धा में स्वर्ण पदक जीता।

AIME-2026 का पूरा नाम क्या है?

Asian-India Maritime Event
ASEAN-India Maritime Exercise
ASEAN International Marine Exercise
Asian International Maritime Exercise

Explanation:

AIME-2026 का पूरा नाम ASEAN-India Maritime Exercise है।
यह ASEAN और भारत के बीच समुद्री सहयोग से संबंधित अभ्यास है।

ASEAN-India Maritime Exercise (AIME-2026) का आयोजन कहाँ शुरू हुआ?

मुंबई, भारत
सिंगापुर
इंडोनेशिया
फिलीपींस

Explanation:

दूसरा ASEAN-India Maritime Exercise (AIME-2026) फिलीपींस के Subic Bay में शुरू हुआ।

ASEAN-India Maritime Exercise (AIME-2026) में भारत की कौन-सी नौसेना पोतों ने भाग लिया?

INS Vikrant और INS Vikramaditya
INS Kolkata और INS Chennai
INS Sahyadri और INS Kulish
INS Shivalik और INS Kiltan

Explanation:

AIME-2026 में भारत की INS Sahyadri और INS Kulish ने भाग लिया।

ASEAN-India Maritime Exercise (AIME-2026) की थीम क्या है?

United for Peace
Maritime Security for All
Stronger Together at Sea
Anchored in Trust, United at Sea

Explanation:

AIME-2026 की थीम “Anchored in Trust, United at Sea” है।
यह समुद्री क्षेत्र में विश्वास और सहयोग की भावना को दर्शाती है।

1 अक्टूबर 2026 को UPSC ने भारत में कितने वर्ष पूरे किए?

75 वर्ष
90 वर्ष
100 वर्ष
125 वर्ष

Explanation:

1 अक्टूबर 2026 को UPSC ने भारत में 100 वर्ष पूरे किए।
प्रथम Indian Public Service Commission की स्थापना 1926 में हुई थी।

प्रथम Indian Public Service Commission की स्थापना किस वर्ष हुई थी?

1919
1926
1935
1947

Explanation:

भारत में प्रथम Indian Public Service Commission की स्थापना 1926 में हुई थी।
इसी ऐतिहासिक क्रम के आधार पर 1 अक्टूबर 2026 को UPSC ने 100 वर्ष पूरे किए।

UPSC वर्तमान में किस प्रकार का निकाय है?

वैधानिक निकाय
कार्यकारी निकाय
अर्ध-न्यायिक निकाय
संवैधानिक निकाय

Explanation:

संघ लोक सेवा आयोग (UPSC) भारत का एक संवैधानिक निकाय है।
इसके संबंध में संविधान में प्रावधान अनुच्छेद 315 से 323 तक दिए गए हैं।

भारतीय संविधान के किन अनुच्छेदों में UPSC से संबंधित प्रावधान हैं?

अनुच्छेद 280–290
अनुच्छेद 300–310
अनुच्छेद 315–323
अनुच्छेद 324–329

Explanation:

संविधान के अनुच्छेद 315 से 323 तक संघ लोक सेवा आयोग और राज्य लोक सेवा आयोगों से संबंधित प्रावधान दिए गए हैं।

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Mechanical

What is a simple machine?

A device that changes the magnitude or direction of force
A device used only for generating electricity
A device used only for measuring temperature
A device used only for storing energy

Explanation:

A simple machine is a mechanical device that helps perform work by changing the magnitude or direction of an applied force.
Examples include the lever, pulley, wheel and axle, inclined plane, screw, and wedge.
The ideal mechanical advantage of a machine is the ratio of output force to input force.

What is mechanical advantage of a machine?

Ratio of output force to input force
Ratio of input force to output force
Ratio of output speed to input speed
Ratio of input work to output work

Explanation:

Mechanical Advantage (MA) = Load / Effort.
A machine having MA greater than 1 multiplies the applied force.
In an ideal machine, input work equals output work.

What is a four-bar linkage?

A mechanism consisting of four rigid links connected by four turning pairs
A mechanism having four gears only
A mechanism having four sliding pairs only
A mechanism consisting of four independent shafts

Explanation:

A four-bar linkage consists of four rigid links connected by four pin joints or turning pairs.
One link is generally fixed and the remaining links produce relative motion.
It is widely used for converting rotary motion into oscillating or other types of motion.

Which link of a four-bar mechanism is generally fixed?

Frame or fixed link
Coupler link
Rocker link
Follower link

Explanation:

The fixed link provides the reference frame for the motion of the other links.
The other three links are generally called the input link, coupler, and output link.

In a four-bar mechanism, the link connecting the crank and rocker is called the:

Coupler link
Frame
Crank
Rocker

Explanation:

The coupler is the floating link that connects the crank and rocker.
It transmits motion from the input crank to the output rocker.

What is the main function of a flywheel?

To reduce fluctuation of speed caused by fluctuation of energy
To control the mean speed of an engine
To increase friction between gears
To increase the fuel supply

Explanation:

A flywheel stores excess energy when the engine produces more energy than required and releases it when the engine produces less energy than required.
It therefore reduces speed fluctuations within a cycle.
A flywheel does not normally regulate the mean speed of an engine; that is primarily the function of a governor.

What is fluctuation of energy in an engine?

The difference between maximum and minimum energy stored in the flywheel during a cycle
The difference between input and output power at all times
The total energy supplied by fuel
The total frictional energy of the engine

Explanation:

During an engine cycle, the turning moment varies, causing the kinetic energy of the rotating parts to fluctuate.
Maximum fluctuation of energy is the difference between maximum and minimum values of energy stored in the flywheel during the cycle.
The flywheel absorbs and releases energy to maintain more uniform speed.

Which device controls the mean speed of an engine when the load changes?

Governor
Flywheel
Clutch
Brake

Explanation:

A governor regulates the fuel or working-fluid supply to maintain approximately constant mean speed when the load changes.
A flywheel mainly reduces cyclic speed fluctuations within an operating cycle.

What is the main purpose of a belt drive?

To transmit power between two shafts
To store hydraulic energy
To measure shaft speed
To reduce the temperature of a bearing

Explanation:

A belt drive transmits mechanical power from a driving shaft to a driven shaft using a flexible belt.
It is suitable when the shafts are separated by a comparatively large distance.

Which type of belt has a trapezoidal cross-section?

V-belt
Flat belt
Round belt
Rope belt

Explanation:

A V-belt has a trapezoidal cross-section and operates in a V-grooved pulley.
The wedging action between the belt and groove increases frictional grip and permits higher power transmission than a flat belt of similar size in many applications.

Which belt is generally preferred for transmitting power over long centre distances?

Flat belt
V-belt
Timing belt only
Toothed gear belt only

Explanation:

Flat belts are commonly used for relatively long centre distances.
V-belts are compact and provide good grip but are generally used for shorter centre distances.
Flat belts transmit power mainly through friction between the belt and pulley.

What is the main advantage of a V-belt over a flat belt?

Higher frictional grip due to wedging action
It requires no pulley
It cannot slip under any condition
It always operates without tension

Explanation:

The V-shaped belt fits into a V-grooved pulley.
The wedging action increases the normal reaction between the belt and pulley surfaces and consequently increases frictional grip.
However, V-belts can still slip under unsuitable operating conditions.

What is a clutch?

A device used to engage or disengage power transmission between two shafts
A device used only to stop a shaft permanently
A device used to measure torque
A device used to store compressed air

Explanation:

A clutch connects the driving shaft to the driven shaft when power transmission is required.
It can also disconnect the driven shaft without stopping the prime mover.
Clutches are widely used in automobiles and machinery.

Which clutch uses friction between flat annular surfaces for power transmission?

Plate clutch
Conical clutch
Centrifugal pump
Gear clutch

Explanation:

A plate clutch transmits torque through friction between one or more pairs of flat friction surfaces.
Single-plate and multi-plate clutches are common types.

In a conical clutch, the friction surfaces are:

Conical
Flat circular
Spherical
Cylindrical only

Explanation:

A conical clutch uses mating conical friction surfaces.
The axial force produces normal pressure on the conical surfaces, allowing torque to be transmitted through friction.

What is the primary function of gears?

To transmit motion and power between shafts with a definite velocity ratio
To store electrical energy
To reduce lubrication requirements to zero
To eliminate all mechanical losses

Explanation:

Gears are toothed mechanical elements used to transmit power and motion between rotating shafts.
They provide a positive drive without the slip associated with friction drives.
They can also change speed, torque, and direction of rotation.

Which type of gear is used to transmit power between parallel shafts with straight teeth?

Spur gear
Bevel gear
Worm gear
Rack and pinion

Explanation:

Spur gears have straight teeth parallel to the axis of rotation.
They are mainly used for parallel shafts.
Helical gears are also used for parallel shafts but have inclined teeth.

Which type of gear is generally used to transmit motion between intersecting shafts?

Bevel gear
Spur gear
Worm gear
Rack and pinion

Explanation:

Bevel gears have conical pitch surfaces and are commonly used for intersecting shafts.
They can transmit motion at different shaft angles, commonly 90°.

Which gear arrangement is commonly used for transmitting motion between non-parallel and non-intersecting shafts?

Worm and worm wheel
Spur gear pair
Bevel gear pair
Rack and pinion

Explanation:

A worm drive consists of a worm and worm wheel and is commonly used for non-parallel, non-intersecting shafts.
It can provide a large speed reduction in a compact arrangement.

What is the gear ratio of a pair of gears in terms of their number of teeth?

Speed ratio = T_driven/T_driver
Speed ratio = T_driver/T_driven in all cases
Speed ratio = T_driver × T_driven
Speed ratio = T_driver + T_driven

Explanation:

For a simple gear pair, N_driverT_driver = N_drivenT_driven.
Therefore, N_driver/N_driven = T_driven/T_driver.
Thus, a larger driven gear rotates at a lower speed than the smaller driving gear.

A 20-tooth gear drives a 60-tooth gear. What is the speed ratio N_driver/N_driven?

Explanation:

Speed ratio = T_driven/T_driver.
Therefore, speed ratio = 60/20 = 3.
If the 20-tooth gear rotates at 900 rpm, the 60-tooth gear rotates at 300 rpm.

Which gear tooth profile is most commonly used in modern power transmission?

Involute profile
Parabolic profile only
Elliptical profile
Circular arc profile only

Explanation:

The involute profile is widely used because it provides a constant velocity ratio even when the centre distance changes slightly.
It is comparatively easy to manufacture and maintain.

What is the main function of a governor?

To regulate the mean speed of an engine according to load changes
To store energy during an engine cycle
To transmit power between shafts
To reduce bearing friction

Explanation:

A governor automatically adjusts the working-fluid or fuel supply as the load changes.
Its purpose is to maintain the mean speed within a desired range.
Flywheel and governor have different functions.

Which of the following is a centrifugal governor?

Watt governor
Dead-weight governor
Pressure governor only
Hydraulic accumulator

Explanation:

The Watt governor is a centrifugal governor.
Centrifugal governors operate using the centrifugal effect produced by rotating masses.
Other examples include Porter and Proell governors.

In a centrifugal governor, the balls move outward when the engine speed:

Increases
Decreases to zero
Remains exactly constant
Becomes independent of load

Explanation:

When speed increases, centrifugal force on the rotating balls increases.
The balls move outward, causing the sleeve mechanism to move and reduce the fuel or working-fluid supply.
This action tends to restore the engine speed.

What is a riveted joint?

A permanent joint made by rivets to connect two or more plates
A temporary joint made only by bolts
A joint made only by welding
A joint used only for gears

Explanation:

Riveting is a permanent mechanical joining process.
Rivets are inserted through holes in the plates and then deformed to form a head, securing the plates together.
Riveted joints were historically common in boilers, bridges, tanks, and structural work.

Which type of riveted joint has the plates overlapping each other?

Lap joint
Butt joint
Welded joint
Flanged joint

Explanation:

In a lap joint, one plate overlaps the other and the rivets pass through the overlapping portion.
In a butt joint, the main plates are placed edge-to-edge and cover plates are generally used.

What is the primary function of a cam?

To convert rotary motion into a prescribed reciprocating or oscillating motion
To store electrical energy
To increase fluid pressure
To join two shafts permanently

Explanation:

A cam is a rotating or sliding machine element that gives a follower a specified motion.
Cams are widely used in engines, automatic machines, and control mechanisms.
The shape of the cam profile determines the follower motion.

In a cam mechanism, the member that follows the cam profile is called the:

Follower
Crank
Rocker
Gear

Explanation:

The follower remains in contact with the cam surface and moves according to the cam profile.
Followers may be translating or oscillating and may have roller, flat-faced, or knife-edge contact.

Which type of follower has a roller at its contacting end?

Roller follower
Knife-edge follower
Flat-faced follower
Spherical follower only

Explanation:

A roller follower uses a small roller to contact the cam.
Rolling contact reduces sliding friction compared with a knife-edge follower and is widely used in high-speed mechanisms.

What is the main function of a bearing?

To support a rotating shaft and reduce friction
To increase shaft friction
To store fuel
To increase gear tooth pressure

Explanation:

Bearings support rotating or moving machine elements while reducing friction and wear.
They are broadly classified into sliding-contact and rolling-contact bearings.
Ball and roller bearings are examples of rolling-contact bearings.

Which bearing primarily supports a radial load?

Radial bearing
Thrust bearing only
Footstep bearing only
Collar bearing only

Explanation:

Radial bearings are designed mainly to support loads acting perpendicular to the shaft axis.
Thrust bearings are designed mainly for loads acting along the shaft axis.

What is friction in a collar bearing?

Friction between the collar and bearing surface due to axial load
Friction between two gear teeth only
Friction between belt and pulley only
Friction in a fluid nozzle

Explanation:

A collar bearing supports an axial or thrust load.
Friction occurs between the rotating collar and the stationary bearing surface.
The frictional torque depends on the load, coefficient of friction, and dimensions of the bearing surfaces.

Which type of bearing is used mainly to support an axial load on a vertical shaft?

Footstep bearing
Journal bearing
Radial ball bearing only
Needle bearing only

Explanation:

A footstep bearing supports the lower end of a vertical shaft and carries axial load.
The end of the shaft rests on the bearing surface.

For a flat collar bearing under uniform pressure, the frictional torque depends on:

The dimensions of the collar, axial load, and coefficient of friction
Only the shaft speed
Only the density of the lubricant
Only the shaft length

Explanation:

For a collar bearing, frictional torque is obtained by integrating the friction force over the bearing area.
For a single collar under uniform pressure, the frictional torque is commonly expressed as T = μWR_m, where μ is coefficient of friction, W is axial load, and R_m is mean radius.
The exact expression for R_m depends on the assumed pressure distribution.

Which machine element is used to transmit motion between two shafts by means of toothed engagement?

Gear
Belt
Clutch
Bearing

Explanation:

Gears transmit power through direct engagement of their teeth.
Unlike friction belt drives, properly meshing gears provide a positive velocity ratio without normal slip.

Which device primarily absorbs and releases energy to smooth cyclic speed fluctuations?

Flywheel
Governor
Clutch
Gearbox

Explanation:

The flywheel stores kinetic energy when the supplied torque exceeds the resisting torque and releases it when the supplied torque is insufficient.
This action smooths the cyclic variation of shaft speed.

What happens to the speed of the driven shaft when a small gear drives a larger gear?

The driven shaft rotates at a lower speed
The driven shaft always rotates faster
Both shafts must rotate at the same speed
The driven shaft does not rotate

Explanation:

For meshing gears, N₁T₁ = N₂T₂.
If T₂ is larger than T₁, then N₂ is smaller than N₁.
Thus, a larger driven gear provides speed reduction and torque multiplication, neglecting losses.

Mechanical

What is the condition for translational equilibrium of a body under coplanar forces?

ΣM = 0 only
ΣF_x = 0 and ΣF_y = 0
ΣF_x = 1 and ΣF_y = 1
ΣF = maximum

Explanation:

For a body to be in translational equilibrium, the resultant force must be zero.
For coplanar forces, this requires ΣF_x = 0 and ΣF_y = 0.

For complete equilibrium of a rigid body in a coplanar force system, which conditions must be satisfied?

ΣF_x = 0 only
ΣF_y = 0 only
ΣM = 0 only
ΣF_x = 0, ΣF_y = 0 and ΣM = 0

Explanation:

A rigid body is in complete equilibrium when there is no resultant translation or rotation.
Therefore, both force equilibrium and moment equilibrium conditions must be satisfied.

Which principle states that the algebraic sum of moments of all forces about a point is zero for a body in rotational equilibrium?

Newton’s first law
Principle of conservation of energy
Moment equilibrium condition
Hooke’s law

Explanation:

For rotational equilibrium, the resultant moment about any reference point must be zero.
Thus, ΣM = 0.

The moment of a force about a point is equal to:

Force × area
Force × perpendicular distance from the point to the line of action
Force ÷ distance
Mass × velocity

Explanation:

The moment of force is M = F × d, where d is the perpendicular distance between the point and the line of action of the force.
The SI unit is N·m.

According to Newton’s first law of motion, a body remains at rest or in uniform straight-line motion when:

A force acts continuously on it
The resultant external force is zero
Its velocity is maximum
Its acceleration is maximum

Explanation:

Newton’s first law is also called the law of inertia.
A body maintains its state of rest or uniform motion unless acted upon by a non-zero resultant external force.

Newton’s second law of motion gives the relationship between force and:

Displacement only
Rate of change of momentum
Potential energy only
Density

Explanation:

Newton’s second law states that force is equal to the rate of change of momentum.
For constant mass, F = ma.

Newton’s third law of motion states that:

Every body remains at rest
Force is always equal to mass × velocity
For every action, there is an equal and opposite reaction
Acceleration is always constant

Explanation:

Newton’s third law states that forces between interacting bodies occur in equal-magnitude and opposite-direction pairs.
The action and reaction forces act on different bodies.

What is the coefficient of friction?

Normal reaction divided by friction
Limiting friction divided by normal reaction
Friction multiplied by normal reaction
Weight divided by friction

Explanation:

The coefficient of static friction is μ = F_lim/N.
At limiting equilibrium, friction reaches its maximum static value.

According to the laws of dry friction, limiting friction is proportional to:

Area of contact only
Velocity
Normal reaction
Temperature only

Explanation:

Coulomb’s law of dry friction gives F_lim = μN.
Thus, limiting friction is proportional to normal reaction for a given pair of surfaces.

When a body is just about to move over a rough horizontal surface, friction is called:

Rolling friction
Kinetic friction
Limiting friction
Fluid friction

Explanation:

When impending motion occurs, static friction reaches its maximum value.
This maximum static friction is called limiting friction.

The angle of friction is the angle between:

Weight and normal reaction
Resultant reaction and normal reaction
Friction and weight
Applied force and displacement

Explanation:

The resultant reaction is the vector sum of normal reaction N and limiting friction F.
If φ is the angle of friction, tan φ = F/N = μ.

What is stress?

Deformation per unit length
Internal resisting force per unit area
Force multiplied by area
Change in volume per unit mass

Explanation:

Stress is the internal resisting force developed per unit cross-sectional area due to an external load.
Normal stress is σ = P/A.
Its SI unit is Pa or N/m².

What is strain?

Force per unit area
Deformation per unit original dimension
Force per unit volume
Mass per unit volume

Explanation:

Strain is the ratio of change in dimension to original dimension.
Longitudinal strain = ΔL/L.
Strain is dimensionless.

Which type of stress is produced when a body is subjected to an axial tensile load?

Shear stress
Bending stress only
Tensile normal stress
Torsional stress only

Explanation:

An axial tensile load tends to elongate the member.
The corresponding normal stress is tensile stress, σ = P/A.

Which type of stress is developed when two parallel forces act tangentially in opposite directions on a body?

Compressive stress
Tensile stress
Shear stress
Bearing stress only

Explanation:

Shear stress acts tangentially to the area and tends to cause one layer of material to slide relative to another.
It is commonly represented by τ.

Hooke’s law states that, within the elastic limit:

Stress is independent of strain
Stress is directly proportional to strain
Stress is inversely proportional to strain
Strain is always zero

Explanation:

Within the elastic limit, stress is proportional to strain.
For direct loading, σ = Eε, where E is Young’s modulus.

What is the elastic limit of a material?

The point at which the material melts
The maximum stress up to which the material returns essentially to its original shape after unloading
The point of fracture only
The point of zero strain

Explanation:

Within the elastic limit, removal of the load allows the material to recover its original dimensions, neglecting very small residual effects.
Beyond the elastic range, permanent deformation may remain.

Young’s modulus is defined as the ratio of:

Shear stress to shear strain
Longitudinal stress to longitudinal strain
Volumetric stress to longitudinal strain
Load to volume

Explanation:

Young’s modulus is E = σ/ε.
It measures the stiffness of a material in axial loading.

Bulk modulus is defined as the ratio of:

Shear stress to shear strain
Volumetric stress to volumetric strain
Longitudinal stress to longitudinal strain
Torque to angular deformation

Explanation:

Bulk modulus K measures resistance to uniform volumetric deformation.
K = −Δp/(ΔV/V), with the negative sign accounting for compression.

Modulus of rigidity is the ratio of:

Normal stress to longitudinal strain
Volumetric stress to volumetric strain
Shear stress to shear strain
Load to displacement

Explanation:

Modulus of rigidity or shear modulus is G = τ/γ.
It measures resistance to shear deformation.

Which elastic constant represents resistance to change in volume?

Young’s modulus
Modulus of rigidity
Bulk modulus
Poisson’s ratio

Explanation:

Bulk modulus measures the resistance of a material to uniform compression and change in volume.

Poisson’s ratio is the ratio of:

Longitudinal strain to lateral strain
Lateral strain to longitudinal strain in magnitude
Stress to strain
Shear stress to shear strain

Explanation:

Poisson’s ratio is ν = − lateral strain/longitudinal strain.
The negative sign reflects the opposite nature of lateral and longitudinal deformation under axial loading.

For a homogeneous beam subjected to transverse loading, the bending moment at a section is associated with:

Axial deformation only
Internal resistance to bending
Fluid pressure
Thermal expansion only

Explanation:

Bending moment at a section represents the internal moment developed to resist the external loading.
It produces bending stresses across the beam section.

What does a shear force diagram represent?

Variation of bending stress only
Variation of internal shear force along the length of a beam
Variation of Young’s modulus
Variation of density

Explanation:

A shear force diagram, or SFD, shows how internal shear force varies from section to section along a beam.

What does a bending moment diagram represent?

Variation of axial strain
Variation of bending moment along the length of a beam
Variation of fluid pressure
Variation of density

Explanation:

A bending moment diagram, or BMD, graphically represents the bending moment at different sections of a beam.

At a point load acting on a beam, the shear force diagram generally shows:

A smooth curve without change
A sudden jump equal to the magnitude of the point load
Always zero
An infinite slope only

Explanation:

A concentrated point load causes a sudden change in shear force.
The magnitude of the jump equals the applied point load, with sign determined by the adopted convention.

At a concentrated point load, the bending moment diagram generally:

Has a sudden jump equal to the load
Remains continuous, although its slope changes
Becomes zero automatically
Becomes infinite

Explanation:

A point load causes a sudden change in shear force, which changes the slope of the BMD.
The bending moment itself remains continuous at an ordinary point load.

At a point where the shear force changes sign from positive to negative, the bending moment is generally:

Minimum only
Maximum
Always zero
Infinite

Explanation:

Since dM/dx = V, a change in shear force from positive to negative indicates that the bending moment changes from increasing to decreasing.
Therefore, the bending moment is maximum at that section.

What is a composite bar?

A bar made only from one material
A bar consisting of two or more different materials acting together
A bar with zero stress
A bar without any deformation

Explanation:

A composite bar contains members of different materials connected so that they act together under load.
Examples include steel and concrete combinations.

For two materials rigidly connected in a composite bar and subjected to the same axial deformation over the same length, the compatibility condition is:

Equal stress in both materials
Equal strain in both materials
Equal Young’s modulus
Equal cross-sectional area

Explanation:

When the members are rigidly connected and have the same original length, their elongations are compatible.
Thus, ε₁ = ε₂ when both experience the same elongation over the same length.

In a composite bar, the total load is equal to:

Stress of one material only
Sum of the loads carried by the individual materials
Young’s modulus of all materials
Total strain multiplied by length

Explanation:

The applied load is shared by the component materials.
Therefore, P = P₁ + P₂ + …

In a composite bar under axial load, the material with higher Young’s modulus generally carries:

No load
Always the same load as the softer material
A greater share of load when the component strains are equal
Only shear load

Explanation:

For equal strain, σ = Eε.
Therefore, a material with higher Young’s modulus develops greater stress and generally carries a greater load for the same area.

Torsion of a circular shaft primarily produces:

Normal tensile stress only
Normal compressive stress only
Shear stress
Hydrostatic stress

Explanation:

A torque applied to a circular shaft produces twisting deformation.
The principal stress associated directly with torsion is shear stress.

For a circular shaft subjected to pure torsion, the torsion equation is:

P = ρAV
T/J = τ/R = Gθ/L
M/I = σ/y
σ = Eε

Explanation:

The torsion equation for a circular shaft is:
T/J = τ/R = Gθ/L
Here, T is torque, J is polar moment of inertia, τ is shear stress, R is outer radius, G is modulus of rigidity, θ is angle of twist and L is shaft length.

In a circular shaft under pure torsion, shear stress is maximum at the:

Centre
Neutral axis only
Outer surface
Centroid only

Explanation:

From τ = Tr/J, shear stress varies linearly with radial distance r.
Therefore, stress is zero at the centre and maximum at the outer surface.

For a solid circular shaft under pure torsion, shear stress at the centre is:

Maximum
Zero
Equal to the surface stress
Infinite

Explanation:

From τ = Tr/J, when r = 0 at the centre, τ = 0.
Shear stress increases linearly from zero at the centre to maximum at the outer surface.

What is the polar moment of inertia of a solid circular shaft of diameter d?

πd⁴/64
πd⁴/32
πd³/32
πd²/4

Explanation:

For a solid circular section:
J = πd⁴/32
The second moment of area about a centroidal axis is I = πd⁴/64.

What is the torsional rigidity of a circular shaft?

E/I
GJ
EI
μ/A

Explanation:

Torsional rigidity is the resistance offered by a shaft to angular twist.
It is represented by GJ, where G is modulus of rigidity and J is polar moment of inertia.

What is buckling of a column?

Uniform shortening under axial load
Lateral instability of a slender column under compressive load
Twisting due to torque
Failure due only to shear

Explanation:

A slender column subjected to sufficient axial compression may become unstable and bend laterally.
This instability is called buckling.

Euler’s column theory is primarily applicable to:

Short columns only
Long slender columns
Thick pressure vessels
Short beams under shear

Explanation:

Euler’s theory assumes an ideal long, slender column and elastic behavior.
It is most suitable for long columns where buckling governs failure.

Euler’s critical buckling load for a column is proportional to:

L²
L
1/L²
1/L

Explanation:

Euler’s critical load is:
P_cr = π²EI/(L_e)²
Therefore, critical load decreases with the square of effective length.

For a column with both ends hinged, the effective length is:

L/2
L
2L
√2L

Explanation:

For a column hinged at both ends, the effective length factor K = 1.
Therefore, L_e = L.

For a column fixed at both ends, the effective length is:

L
L/√2
L/2
2L

Explanation:

For ideal fixed-fixed end conditions, the effective length factor is K = 0.5.
Therefore, L_e = L/2.

For a column fixed at one end and free at the other, the effective length is:

L/2
L
2L
L/√2

Explanation:

For an ideal fixed-free column, the effective length factor K = 2.
Thus, L_e = 2L.

According to Euler’s theory, the critical load depends on:

Only the material density
Young’s modulus, moment of inertia and effective length
Only the cross-sectional area
Only the column weight

Explanation:

Euler’s critical load is P_cr = π²EI/L_e².
Thus, it depends on Young’s modulus E, second moment of area I and effective length L_e.

Rankine’s formula is mainly used for:

Only very short columns
Columns of intermediate length by considering both crushing and buckling effects
Only thin pressure vessels
Only torsion members

Explanation:

Rankine’s theory provides an empirical approach that accounts for both crushing and buckling tendencies.
It is particularly useful for columns where Euler’s assumptions alone are not adequate.

Which column theory is more suitable for intermediate-length columns?

Euler’s theory alone
Rankine’s theory
Bernoulli’s fluid theory
Hooke’s law alone

Explanation:

Rankine’s formula bridges the behavior between short-column crushing and long-column buckling.
It is therefore commonly used for intermediate columns.

According to Rankine’s formula, the crippling load is generally expressed as:

P = σA only
P = σ_cA/[1 + α(L_e/k)²]
P = EI/L
P = πEI/L

Explanation:

A common Rankine form is:
P = σ_cA/[1 + α(L_e/k)²]
Here, σ_c is crushing stress, A is area, L_e is effective length, k is radius of gyration and α is the Rankine constant.

What is a thin-walled pressure vessel?

A vessel with wall thickness greater than its diameter
A pressure vessel having relatively small wall thickness compared with its diameter
A vessel having zero internal pressure
A solid cylinder without a cavity

Explanation:

A thin-walled pressure vessel has a small wall thickness compared with its diameter.
For such vessels, membrane-stress theory is commonly used.

For a thin cylindrical pressure vessel, the hoop stress is:

pd/4t
pd/2t
pd/t
pt/2d

Explanation:

For a thin cylindrical vessel:
Hoop stress, σ_h = pd/(2t)
where p is internal pressure, d is internal diameter and t is wall thickness.

For a thin cylindrical pressure vessel, the longitudinal stress is:

pd/2t
pd/4t
pd/t
2pd/t

Explanation:

For a thin cylindrical vessel:
Longitudinal stress, σ_l = pd/(4t)
Thus, hoop stress is twice the longitudinal stress.

In a thin cylindrical pressure vessel, the hoop stress is how many times the longitudinal stress?

Half
Equal
Twice
Four times

Explanation:

Hoop stress = pd/(2t).
Longitudinal stress = pd/(4t).
Therefore, σ_h/σ_l = 2.

Hoop stress in a thin cylindrical pressure vessel acts:

Along the longitudinal axis of the cylinder
Circumferentially around the cylinder
Only through the thickness
Radially inward only

Explanation:

Hoop stress is also called circumferential stress.
It acts around the circumference and tends to split the cylinder along its longitudinal direction.

Longitudinal stress in a thin cylindrical pressure vessel acts:

Circumferentially
Along the longitudinal axis of the cylinder
Only radially
Only through the wall thickness

Explanation:

Longitudinal stress acts along the axis of the cylinder.
It tends to separate the end caps from the cylindrical wall.

For a thin spherical pressure vessel, the membrane stress is:

pd/t
pd/2t
pd/4t
pd/8t

Explanation:

For a thin spherical vessel:
σ = pd/(4t)
The stress is the same in all tangential directions at a point because of spherical symmetry.

Compared with a thin cylindrical vessel of the same diameter, pressure and thickness, the membrane stress in a thin spherical vessel is:

Twice as high
Equal to the hoop stress
Half the hoop stress of the cylinder
Four times as high

Explanation:

Cylinder hoop stress = pd/(2t).
Sphere stress = pd/(4t).
Therefore, the spherical-vessel membrane stress is half the cylindrical hoop stress for the same p, d and t.

Which stress is generally critical in the design of a thin cylindrical pressure vessel?

Longitudinal stress
Hoop stress
Radial stress only
Shear stress due to torque

Explanation:

For a thin cylinder, hoop stress is twice the longitudinal stress.
Therefore, hoop stress generally governs the membrane-stress design.

If the internal pressure of a thin cylindrical vessel is doubled while diameter and thickness remain unchanged, the hoop stress will:

Become half
Remain unchanged
Become double
Become four times

Explanation:

Hoop stress is σ_h = pd/(2t).
Therefore, stress is directly proportional to internal pressure.
Doubling pressure doubles hoop stress.

If the wall thickness of a thin cylindrical pressure vessel is doubled while pressure and diameter remain unchanged, the hoop stress will:

Become double
Become half
Remain unchanged
Become four times

Explanation:

Hoop stress is inversely proportional to wall thickness:
σ_h = pd/(2t).
Therefore, doubling t reduces hoop stress to half.

Mechanical

Which of the following best defines a fluid?

A substance that cannot change its shape
A substance that resists all deformation permanently
A substance that continuously deforms under an applied shear stress
A substance having zero density

Explanation:

A fluid cannot sustain a shear stress at rest and continuously deforms when subjected to shear stress.
Liquids and gases are classified as fluids.

Which of the following is an ideal fluid?

A fluid having very high viscosity
A hypothetical fluid having zero viscosity and generally treated as incompressible
A fluid having infinite density
A fluid having maximum friction

Explanation:

An ideal fluid is a hypothetical fluid with zero viscosity.
In basic fluid mechanics, it is also generally assumed to be incompressible.
Therefore, an ideal fluid has no viscous shear resistance.

Which property is neglected for an ideal fluid?

Density
Pressure
Viscosity
Gravity

Explanation:

An ideal fluid is assumed to have zero viscosity.
Therefore, no energy is lost due to viscous friction in ideal-fluid analysis.

Which of the following is a characteristic of a real fluid?

Zero viscosity
No internal friction
Non-zero viscosity
Zero density

Explanation:

All actual fluids possess viscosity to some extent.
Viscosity represents the internal resistance of a fluid to relative motion between adjacent fluid layers.

Which statement about an ideal fluid is correct?

It has infinite viscosity
It has zero shear stress for any finite rate of deformation
It always has zero pressure
It cannot flow

Explanation:

For an ideal fluid, viscosity μ = 0.
From Newton’s law of viscosity, τ = μ(du/dy), so shear stress due to viscosity is zero.

Which of the following is a property of a real fluid that causes resistance to flow?

Specific weight
Surface tension only
Viscosity
Vapour pressure only

Explanation:

Viscosity is the property of a fluid that offers resistance to relative motion between its layers.
Higher viscosity generally means greater resistance to flow under comparable conditions.

Newton’s law of viscosity relates shear stress to:

Pressure only
Density only
Velocity gradient
Temperature only

Explanation:

Newton’s law of viscosity is:
τ = μ(du/dy)
Thus, shear stress is proportional to the velocity gradient normal to the direction of flow.

Which equation represents Newton’s law of viscosity?

τ = ρgh
τ = pA
τ = μ(du/dy)
τ = ρV²

Explanation:

Newton’s law of viscosity is expressed as τ = μ(du/dy).
Here, τ is shear stress, μ is dynamic viscosity and du/dy is the velocity gradient.

In Newton’s law of viscosity, μ represents:

Kinematic viscosity
Dynamic viscosity
Density
Specific gravity

Explanation:

In τ = μ(du/dy), μ is the coefficient of dynamic or absolute viscosity.
Its SI unit is Pa·s or N·s/m².

What is the SI unit of dynamic viscosity?

m²/s
N/m²
Pa·s
kg/m³

Explanation:

The SI unit of dynamic viscosity is Pa·s.
It is also equivalent to N·s/m² or kg/(m·s).

What is the SI unit of kinematic viscosity?

Pa·s
N·s/m²
m²/s
kg/m³

Explanation:

Kinematic viscosity is defined as:
ν = μ/ρ
Its SI unit is m²/s.

What is the relationship between dynamic and kinematic viscosity?

ν = μρ
ν = μ/ρ
μ = ν/ρ
ν = ρ/μ

Explanation:

Kinematic viscosity is dynamic viscosity divided by density.
ν = μ/ρ

A fluid that obeys Newton’s law of viscosity is called:

Ideal fluid
Newtonian fluid
Perfect gas
Compressible fluid

Explanation:

A Newtonian fluid obeys the linear relationship τ = μ(du/dy).
At a given temperature and pressure, its viscosity remains essentially independent of the velocity gradient.

Which of the following is a Newtonian fluid?

Toothpaste
Paint
Water
Blood

Explanation:

Water behaves approximately as a Newtonian fluid under ordinary conditions.
Other common Newtonian fluids include air and many simple oils.

For a Newtonian fluid, the relationship between shear stress and velocity gradient is:

Nonlinear
Exponential
Linear
Independent of velocity gradient

Explanation:

For a Newtonian fluid:
τ = μ(du/dy)
Therefore, shear stress varies linearly with velocity gradient when μ is constant.

Which of the following is generally classified as a non-Newtonian fluid?

Water
Air
Toothpaste
Simple mineral oil under suitable conditions

Explanation:

Toothpaste exhibits non-Newtonian behavior.
Its apparent viscosity changes with shear rate and it may require a finite stress before significant flow occurs.

Which statement is correct for a non-Newtonian fluid?

Shear stress is always directly proportional to velocity gradient
Viscosity is always constant under all conditions
The relationship between shear stress and velocity gradient is not necessarily linear
It must have zero viscosity

Explanation:

Non-Newtonian fluids do not obey the simple linear Newtonian relationship.
Their apparent viscosity may depend on shear rate, time or other factors.

Which of the following fluids generally exhibits shear-thinning behavior?

Water
Paint
Ideal fluid
Air

Explanation:

Shear-thinning fluids show decreasing apparent viscosity as shear rate increases.
Many paints, polymer solutions and some biological fluids exhibit shear-thinning behavior.

A fluid whose apparent viscosity decreases as the rate of shear increases is called:

Dilatant fluid
Pseudoplastic fluid
Newtonian fluid
Ideal fluid

Explanation:

Pseudoplastic fluids are shear-thinning fluids.
Their apparent viscosity decreases with increasing shear rate.

A fluid whose apparent viscosity increases with increasing shear rate is called:

Pseudoplastic fluid
Newtonian fluid
Dilatant fluid
Ideal fluid

Explanation:

Dilatant fluids are shear-thickening fluids.
Their apparent viscosity increases as the shear rate increases.

Which type of non-Newtonian fluid requires a finite yield stress before it begins to flow?

Newtonian fluid
Pseudoplastic fluid without yield stress
Plastic or Bingham plastic fluid
Ideal fluid

Explanation:

A Bingham plastic requires a yield stress before appreciable continuous flow occurs.
Toothpaste and some slurries are common examples of materials that can show yield-stress behavior.

Which graph correctly represents a Newtonian fluid when shear stress is plotted against velocity gradient?

A horizontal curve
A vertical curve
A straight line passing through the origin
A random curve

Explanation:

For a Newtonian fluid, τ = μ(du/dy).
Therefore, a plot of shear stress against velocity gradient is a straight line through the origin, with slope equal to μ.

In a Newtonian fluid, the slope of the shear stress versus velocity gradient graph represents:

Density
Pressure
Dynamic viscosity
Specific gravity

Explanation:

From τ = μ(du/dy), the slope of the τ versus du/dy graph is μ.
Thus, the slope represents dynamic viscosity.

If the dynamic viscosity of a Newtonian fluid is doubled while the velocity gradient remains constant, the shear stress will:

Become half
Remain unchanged
Become double
Become four times

Explanation:

Newton’s law gives τ = μ(du/dy).
If μ is doubled and du/dy remains constant, τ also doubles.

If the velocity gradient in a Newtonian fluid is doubled while viscosity remains constant, the shear stress will:

Become half
Remain unchanged
Become double
Become four times

Explanation:

Since τ = μ(du/dy), shear stress is directly proportional to velocity gradient for a Newtonian fluid.
Therefore, doubling the velocity gradient doubles the shear stress.

Which statement correctly distinguishes an ideal fluid from a real fluid?

Ideal fluid has density, while real fluid does not
Ideal fluid has zero viscosity, while real fluids have viscosity
Ideal fluid cannot flow, while real fluid can flow
Ideal fluid always has higher density

Explanation:

An ideal fluid is a theoretical model with zero viscosity.
Real fluids have finite viscosity and therefore experience viscous resistance.

What is a compressible fluid?

A fluid whose pressure is always zero
A fluid whose density changes appreciably with pressure or other flow conditions
A fluid having zero viscosity
A fluid that cannot flow

Explanation:

In compressible flow, changes in pressure can produce significant changes in density.
Gases are generally treated as compressible fluids, especially when pressure or velocity changes are significant.

Which fluid is generally treated as compressible in fluid mechanics?

Water
Mercury
Air
Hydraulic oil

Explanation:

Gases such as air have density changes that can become significant with changes in pressure and temperature.
Therefore, air is generally treated as a compressible fluid.

Which fluid is generally treated as incompressible under ordinary engineering conditions?

Air
Natural gas
Water
Steam

Explanation:

Liquids have relatively small changes in density with pressure.
Therefore, water is commonly treated as incompressible in many engineering calculations.

What is an incompressible fluid?

A fluid having zero pressure
A fluid having zero viscosity
A fluid whose density remains essentially constant
A fluid having infinite velocity

Explanation:

For an incompressible fluid, density is treated as constant during the flow.
This assumption greatly simplifies the continuity and energy equations.

Which of the following statements about liquids is generally correct?

Liquids are highly compressible
Liquids are generally treated as incompressible
Liquids always have zero viscosity
Liquids cannot exert pressure

Explanation:

Liquids do have finite compressibility, but their density changes are usually small compared with gases.
Hence, they are commonly approximated as incompressible in engineering applications.

For an incompressible fluid, the density during a flow is:

Always zero
Always increasing
Approximately constant
Always decreasing

Explanation:

The defining approximation for an incompressible fluid is constant density.
Therefore, ρ₁ = ρ₂ in the simplified continuity equation.

For a steady incompressible flow, the continuity equation is:

ρAV = constant with changing density
AV = constant
pV = constant
μAV = constant

Explanation:

The general steady-flow mass conservation equation is ρAV = constant.
For incompressible flow, ρ is constant, so it reduces to AV = constant.

Which of the following is most likely to require compressible-flow analysis?

Slow flow of water through a large pipe
Static water in a tank
High-speed flow of air through a nozzle
Slow flow of hydraulic oil

Explanation:

At sufficiently high gas velocities, density changes can become significant.
High-speed gas flow through nozzles is therefore commonly analyzed as compressible flow.

Which classification is based on whether density changes significantly during flow?

Ideal and real fluids
Newtonian and non-Newtonian fluids
Compressible and incompressible fluids
Laminar and turbulent fluids

Explanation:

Compressible/incompressible classification concerns the variation of fluid density during flow.
Newtonian/non-Newtonian classification concerns the relationship between shear stress and deformation rate.
Ideal/real classification is primarily related to viscosity and viscous effects.

Which classification is based on the relationship between shear stress and velocity gradient?

Compressible and incompressible
Ideal and real
Newtonian and non-Newtonian
Laminar and turbulent

Explanation:

Newtonian fluids obey τ = μ(du/dy), giving a linear relationship.
Non-Newtonian fluids do not necessarily follow this linear relationship.

Which statement is correct about viscosity of gases and liquids with increasing temperature?

Viscosity of liquids generally increases and gases decrease
Viscosity of liquids generally decreases, while viscosity of gases generally increases
Both always increase
Both always decrease

Explanation:

For most liquids, increasing temperature reduces intermolecular cohesive effects and decreases viscosity.
For gases, increasing temperature generally increases molecular momentum transfer and hence dynamic viscosity.

Which of the following has the highest viscosity among the listed fluids under ordinary conditions?

Air
Water
Heavy lubricating oil
Steam

Explanation:

Heavy lubricating oils have much greater resistance to flow than air or water.
Viscosity is a measure of internal resistance to fluid motion.

Which of the following statements is correct?

All real fluids are ideal fluids
All gases are incompressible under every condition
Ideal fluid is a theoretical model, whereas real fluids have viscosity
Newtonian fluids always have zero viscosity

Explanation:

Ideal fluid is an approximation used to simplify fluid-flow analysis.
Real fluids possess viscosity.
A Newtonian fluid can have finite viscosity; Newtonian behavior means the shear stress–velocity-gradient relationship is linear.

Mechanical

What is pressure at a point in a fluid at rest?

The force acting parallel to the surface per unit area
The normal force acting per unit area
The weight of fluid per unit volume
The volume of fluid per unit mass

Explanation:

Pressure is the normal force exerted by a fluid per unit area.
Pressure = Force/Area.
In a fluid at rest, shear stress is zero, so pressure acts normally on any surface.

What is the SI unit of pressure?

N
N/m
N/m²
m²/N

Explanation:

The SI unit of pressure is pascal (Pa).
1 Pa = 1 N/m².

In a fluid at rest, pressure at a point acts:

Only vertically downward
Only horizontally
Equally in all directions
Only upward

Explanation:

According to Pascal’s law, pressure at a point in a static fluid is transmitted equally in all directions.
Therefore, pressure at a point has the same magnitude regardless of the orientation of the imaginary surface passing through that point.

In a static fluid, pressure generally increases with:

Decrease in depth
Increase in depth
Decrease in density only
Decrease in gravity

Explanation:

For a fluid at rest, pressure increases with depth according to p = p₀ + ρgh.
Thus, points deeper below the free surface experience greater pressure.

What is the hydrostatic pressure at a depth h below the free surface of a liquid having density ρ?

ρ/hg
h/ρg
ρgh
ρg/h

Explanation:

The gauge pressure due to the liquid column is:
p = ρgh
Here, ρ is density, g is gravitational acceleration and h is depth below the free surface.

What is gauge pressure?

Pressure measured relative to absolute vacuum
Pressure measured relative to atmospheric pressure
Pressure equal to vapour pressure
Pressure due only to liquid weight

Explanation:

Gauge pressure is the pressure above atmospheric pressure.
p_gauge = p_absolute − p_atmospheric.
It can be positive or negative.

What is the relationship between absolute pressure and gauge pressure?

p_absolute = p_gauge − p_atm
p_absolute = p_gauge + p_atm
p_absolute = p_atm − p_gauge
p_absolute = p_gauge

Explanation:

Absolute pressure is measured from absolute vacuum.
Therefore, p_absolute = p_atmospheric + p_gauge.

Which instrument is commonly used for measuring pressure difference between two points in a fluid system?

Thermometer
Barometer
Differential manometer
Hydrometer

Explanation:

A differential manometer measures the pressure difference between two points.
It commonly uses a manometric liquid of known density to determine the pressure difference from the difference in liquid levels.

What is the basic principle of a manometer?

Conservation of momentum
Conservation of mass
Hydrostatic pressure balance
Newton’s law of viscosity

Explanation:

A manometer works by balancing pressure with the weight of liquid columns.
The analysis is based on the hydrostatic relation p = ρgh.

Which type of manometer consists of a transparent tube bent into the shape of the letter U?

Inclined manometer
U-tube manometer
Bourdon gauge
Piezoelectric pressure gauge

Explanation:

A U-tube manometer consists of a U-shaped tube partially filled with a manometric liquid.
The difference in liquid levels is used to determine pressure or pressure difference.

A simple U-tube manometer is commonly used to measure:

Temperature
Flow velocity only
Pressure or pressure difference
Fluid viscosity directly

Explanation:

Depending on its arrangement, a U-tube manometer can measure gauge pressure, vacuum pressure or pressure difference between two points.

Which liquid is commonly used as a manometric liquid for measuring relatively high pressure differences?

Water only
Mercury
Mercury
Petrol

Explanation:

Mercury has a high density, approximately 13.6 times that of water.
Therefore, a relatively small mercury column can balance a large pressure difference.
Other liquids may also be used depending on the application.

Why is a liquid of high density such as mercury used in many manometers?

It produces very large columns
It has zero density
It produces a smaller column height for a given pressure difference
It cannot transmit pressure

Explanation:

From p = ρgh, for a given pressure difference, increasing density decreases the required height difference.
This makes high-density liquids useful for measuring relatively high pressures with compact instruments.

What is the main advantage of an inclined-tube manometer?

It measures temperature directly
It provides greater sensitivity for small pressure differences
It eliminates atmospheric pressure
It is suitable only for gases at very high pressure

Explanation:

In an inclined manometer, a small vertical movement produces a longer movement along the inclined tube.
Therefore, small pressure differences can be measured more accurately.

An inclined manometer is particularly suitable for measuring:

Very high pressure only
Small pressure differences
Temperature differences
Liquid density directly

Explanation:

The inclined tube magnifies the movement of the manometric liquid along the tube.
This increases sensitivity and makes it useful for small pressure differences.

Which statement about pressure in a continuous static liquid is correct?

Pressure is always zero at every point
Pressure decreases with depth
Points at the same horizontal level have the same pressure
Pressure depends only on container shape

Explanation:

For the same continuous liquid at rest, pressure at the same elevation is equal.
It does not depend on the shape of the container.
This is associated with the hydrostatic principle and is often called the hydrostatic paradox when discussing different container shapes.

Which of the following does NOT directly affect hydrostatic pressure at a given depth below a free surface?

Fluid density
Depth
Acceleration due to gravity
Shape of the container

Explanation:

Hydrostatic gauge pressure is p = ρgh.
Thus, it depends on density, gravity and depth, but not on the shape of the container.

What is a streamline?

A line of constant pressure
A line of constant temperature
A line whose tangent at every point gives the instantaneous direction of fluid velocity
A line connecting points of equal density

Explanation:

A streamline is an imaginary curve drawn in a flowing fluid such that the tangent at any point gives the direction of the velocity vector at that point.
There is no flow across a streamline under the idealized instantaneous definition.

Two streamlines in a fluid flow cannot intersect because:

Pressure becomes zero
Density becomes infinite
There would be two different velocity directions at the same point
Temperature would become constant

Explanation:

At a particular instant, a fluid particle at a point can have only one velocity direction.
If two streamlines intersected, they would indicate two different velocity directions at the same point, which is physically impossible for ordinary flow.

What is laminar flow?

Flow with random large-scale fluctuations
Flow in which fluid particles move in relatively smooth and orderly layers
Flow with maximum turbulence
Flow with zero velocity

Explanation:

In laminar flow, fluid particles move in smooth, relatively parallel layers with limited transverse mixing.
For pipe flow, laminar flow generally occurs at Reynolds number below about 2300.

What is turbulent flow?

Flow consisting of perfectly parallel layers
Flow characterized by irregular fluctuations and strong mixing
Flow with zero pressure
Flow occurring only in stationary fluids

Explanation:

Turbulent flow contains irregular velocity and pressure fluctuations and significant mixing.
For flow through a circular pipe, turbulent flow is generally associated with Reynolds number above about 4000.

For flow through a circular pipe, laminar flow generally occurs when Reynolds number is:

Greater than 10,000
Between 4000 and 10,000
Less than about 2300
Exactly 4000

Explanation:

For internal flow through a circular pipe:
Re < 2300: generally laminar
Re ≈ 2300 to 4000: transition region
Re > 4000: generally turbulent

For flow through a circular pipe, turbulent flow is generally obtained when Reynolds number is:

Less than 500
Less than 1000
Between 1000 and 2000
Greater than about 4000

Explanation:

For internal pipe flow, Reynolds number above approximately 4000 generally indicates turbulent flow.
The exact transition behavior can depend on disturbances and inlet conditions.

Which dimensionless number is primarily used to distinguish laminar and turbulent flow?

Mach number
Froude number
Reynolds number
Prandtl number

Explanation:

Reynolds number represents the ratio of inertial forces to viscous forces.
For pipe flow, Re = ρVD/μ = VD/ν.

Which expression represents Reynolds number for flow through a circular pipe?

ρμVD
ρVD/μ
μVD/ρ
ρD/μV

Explanation:

For circular pipe flow, Reynolds number is:
Re = ρVD/μ = VD/ν
Here, ρ is density, V is mean velocity, D is pipe diameter, μ is dynamic viscosity and ν is kinematic viscosity.

What is meant by internal flow?

Flow completely outside a body
Flow bounded by a solid surface, such as flow inside a pipe or duct
Flow only in open oceans
Flow without viscosity

Explanation:

Internal flow occurs within a conduit such as a pipe, duct or channel with boundaries that constrain the flow.
Pipe flow is a common example of internal flow.

What is meant by external flow?

Flow only inside a closed pipe
Flow over or around a solid body immersed in a fluid
Flow through a capillary tube
Flow in a completely enclosed tank at rest

Explanation:

External flow occurs when fluid moves around an immersed body.
Examples include airflow over an aircraft wing, car or cylinder.

Which of the following is an example of internal fluid flow?

Air flowing around an automobile
Water flowing around a submerged sphere
Water flowing through a pipe
Wind flowing over an aircraft wing

Explanation:

Water flowing inside a pipe is an internal flow because the pipe walls completely constrain the fluid.
Flow around a car, sphere or wing is external flow.

Which of the following is an example of external flow?

Water flowing through a pipeline
Oil flowing through a hydraulic cylinder passage
Air flowing over an aircraft wing
Water flowing through a nozzle

Explanation:

Air flowing over an aircraft wing is external flow because the fluid moves around an immersed solid body.

What does the continuity equation represent for fluid flow?

Conservation of energy
Conservation of mass
Conservation of temperature
Conservation of viscosity

Explanation:

The continuity equation is derived from conservation of mass.
For steady flow, the mass flow rate entering a control volume equals the mass flow rate leaving it when there is no accumulation.

What is the continuity equation for steady incompressible flow through a pipe?

pV = constant
A₁V₁ = A₂V₂
p₁A₁ = p₂A₂
V₁/A₁ = V₂/A₂

Explanation:

For steady incompressible flow, density is constant.
Therefore, conservation of mass gives:
A₁V₁ = A₂V₂
The discharge is Q = AV.

For steady compressible flow, the general continuity relation between two sections is:

A₁V₁ = A₂V₂ only
ρ₁A₁V₁ = ρ₂A₂V₂
ρ₁A₁ = ρ₂A₂V₁V₂
A₁/V₁ = A₂/V₂

Explanation:

For steady flow, conservation of mass requires constant mass flow rate.
Therefore, ρAV = constant.
For incompressible flow, density is constant and the relation reduces to AV = constant.

What is the discharge through a pipe carrying an incompressible fluid?

Q = A/V
Q = V/A
Q = AV
Q = ρAV

Explanation:

Volumetric discharge is the volume of fluid flowing per unit time.
For a uniform section, Q = AV.
Its SI unit is m³/s.

If the cross-sectional area of a pipe is reduced to half for steady incompressible flow, the velocity will:

Become half
Remain unchanged
Become twice
Become four times

Explanation:

From A₁V₁ = A₂V₂:
If A₂ = A₁/2, then V₂ = 2V₁.
Thus, velocity doubles.

A pipe has an area of 0.02 m² and carries water at 3 m/s. What is the discharge?

0.006 m³/s
0.06 m³/s
0.6 m³/s
6 m³/s

Explanation:

Discharge Q = AV.
Q = 0.02 × 3 = 0.06 m³/s.

In steady flow, which quantity remains constant along a stream tube when there is no mass accumulation?

Pressure only
Velocity only
Mass flow rate
Temperature only

Explanation:

For steady flow without accumulation, the mass flow rate remains constant.
Thus, ρAV = constant.
Pressure and velocity can change from one section to another.

Which statement correctly describes a streamline in a steady flow?

It always represents a constant-pressure line
Its tangent gives the local fluid velocity direction
It is always perpendicular to the velocity
It represents a line of constant density

Explanation:

A streamline is defined by the instantaneous velocity direction.
In a steady flow, streamlines coincide with particle paths and streaklines under the usual ideal conditions of a steady velocity field.

Mechanical

Which equation is used to describe the energy conservation of an ideal fluid flowing steadily along a streamline?

Continuity equation
Bernoulli’s equation
Newton’s law of viscosity
Pascal’s law

Explanation:

Bernoulli’s equation is based on the conservation of mechanical energy for an ideal fluid flowing steadily along a streamline.
For an ideal fluid, the flow is assumed to be incompressible and non-viscous.

Which of the following is the standard form of Bernoulli’s equation in terms of head?

p/ρg + V²/g + z = constant
p/ρg + V²/2g + z = constant
p/ρg + V²/2 + gz = constant
p/ρ + V²/2g + z = constant

Explanation:

Bernoulli’s equation in head form is:
p/ρg + V²/2g + z = constant
Here, p/ρg is pressure head, V²/2g is velocity head, and z is elevation head.

Bernoulli’s equation is fundamentally based on which principle?

Conservation of mass
Conservation of momentum
Conservation of energy
Conservation of angular momentum

Explanation:

Bernoulli’s equation represents conservation of mechanical energy per unit weight of fluid.
The three main forms of energy are pressure energy, kinetic energy and potential energy.

What is the pressure head of a flowing fluid?

V²/2g
z
p/ρg
ρg/p

Explanation:

Pressure head represents pressure energy per unit weight of fluid.
Pressure head = p/ρg, where p is pressure, ρ is density and g is acceleration due to gravity.
Its unit is metre of fluid.

What is meant by velocity head?

p/ρg
z
V²/2g
V/g

Explanation:

Velocity head represents kinetic energy per unit weight of fluid.
Velocity head = V²/2g.
It is expressed in metres of fluid.

What is elevation head in Bernoulli’s equation?

p/ρg
V²/2g
z
ρgV

Explanation:

The elevation head represents the potential energy per unit weight of fluid.
It is equal to the vertical elevation z measured from a selected datum.

What is the total head of a fluid in Bernoulli’s equation?

p/ρg + V²/2g
V²/2g + z
p/ρg + V²/2g + z
p/ρ + V²/2 + z

Explanation:

Total head is the sum of pressure head, velocity head and elevation head.
Total head = pressure head + velocity head + elevation head.
Therefore, H = p/ρg + V²/2g + z.

What is the unit of total head in Bernoulli’s equation?

Pa
N
J/kg
m of fluid

Explanation:

When Bernoulli’s equation is expressed in head form, each energy term is divided by g.
Therefore, pressure head, velocity head, elevation head and total head are expressed in metres of fluid.

For an ideal fluid flowing steadily along a streamline, the total head is:

Always increasing
Always decreasing
Constant
Zero

Explanation:

For steady, incompressible, inviscid flow along a streamline with no pump, turbine or other energy interaction, Bernoulli’s equation gives a constant total head.

Which of the following assumptions is associated with the ideal-fluid form of Bernoulli’s equation?

Highly viscous flow
Compressible flow with large density changes
Inviscid and incompressible flow
Unsteady flow with large energy losses

Explanation:

The basic Bernoulli equation assumes steady flow, incompressible fluid, negligible viscosity and application along a streamline.
For flow between different streamlines, additional conditions are required, such as irrotational flow.

In a horizontal pipe of varying cross-section carrying an ideal incompressible fluid, if the velocity increases, the static pressure generally:

Increases
Decreases
Remains unchanged
Becomes zero

Explanation:

For a horizontal pipe, z is constant.
Therefore, Bernoulli’s equation becomes p/ρg + V²/2g = constant.
If velocity increases, velocity head increases and static pressure head decreases.

Which principle explains the decrease in pressure when fluid velocity increases in a horizontal ideal-flow passage?

Pascal’s law
Newton’s third law
Bernoulli’s principle
Archimedes’ principle

Explanation:

Bernoulli’s principle states that, for steady ideal flow along a streamline, an increase in kinetic energy per unit weight is accompanied by a corresponding decrease in pressure energy when elevation remains constant.

What happens to the velocity of an incompressible fluid when the cross-sectional area of a pipe is reduced?

Velocity decreases
Velocity becomes zero
Velocity increases
Velocity remains constant for all conditions

Explanation:

From the continuity equation, Q = AV.
For constant discharge Q, velocity is inversely proportional to area.
Therefore, reducing the pipe area increases fluid velocity.

Which equation is commonly used along with Bernoulli’s equation to determine velocity changes in a pipe?

Gas equation
Continuity equation
Newton’s law of cooling
Fourier’s law

Explanation:

The continuity equation for steady incompressible flow is Q = AV.
Bernoulli’s equation gives the energy relationship, while the continuity equation relates velocity to flow area.

Which of the following is an application of Bernoulli’s equation?

Measurement of viscosity using a viscometer
Flow measurement using a venturimeter
Measurement of temperature using a thermometer
Measurement of mass using a weighing balance

Explanation:

A venturimeter uses the pressure difference between its inlet and throat to determine fluid discharge.
Bernoulli’s equation and the continuity equation are used in its analysis.

Which device is primarily used to measure fluid velocity based on Bernoulli’s principle and stagnation pressure?

Venturimeter
Orifice meter
Pitot tube
Rotameter

Explanation:

A Pitot tube measures fluid velocity by converting kinetic energy into pressure at a stagnation point.
For ideal flow, V = √[2(p₀ − p)/ρ].

At the stagnation point of an ideal flow, the fluid velocity is:

Maximum
Equal to inlet velocity
Zero
Infinite

Explanation:

A stagnation point is a point where the fluid comes to rest relative to the measuring device.
Therefore, velocity at the stagnation point is zero and the corresponding pressure is called stagnation pressure.

In a venturimeter, the velocity of fluid is maximum at the:

Inlet
Convergent section entrance
Throat
Outlet of diffuser

Explanation:

The throat has the minimum cross-sectional area.
For incompressible steady flow, Q = AV, so the velocity becomes maximum at the throat.
The static pressure is correspondingly minimum at the throat under ideal conditions.

Which part of a venturimeter helps recover pressure after the throat?

Inlet pipe
Convergent section
Diffuser
Throat

Explanation:

The diffuser is the gradually expanding section after the throat.
As velocity decreases in the diffuser, part of the kinetic energy is converted back into pressure energy.
A gradual expansion helps reduce flow separation and energy loss.

Bernoulli’s equation can be applied directly between two points when they lie on:

Different unrelated flow systems
The same streamline for the basic steady-flow form
Different fluids
Different independent pipes without connection

Explanation:

The basic Bernoulli equation is applied between two points on the same streamline for steady, incompressible, inviscid flow.
For irrotational flow, the Bernoulli constant can be the same throughout the flow field.

Which energy term represents the potential energy per unit weight of a fluid?

Pressure head
Velocity head
Elevation head
Friction head

Explanation:

Elevation head is z and represents gravitational potential energy per unit weight.
Pressure head represents pressure energy, while velocity head represents kinetic energy.

Which energy term represents kinetic energy per unit weight in Bernoulli’s equation?

Pressure head
Velocity head
Elevation head
Datum head

Explanation:

Kinetic energy per unit mass is V²/2.
Dividing by g to express energy per unit weight gives the velocity head V²/2g.

Which energy term is represented by p/ρg in Bernoulli’s equation?

Elevation head
Velocity head
Pressure head
Friction head

Explanation:

Pressure head is p/ρg.
It represents the pressure energy available per unit weight of fluid.

If the elevation and pressure heads remain constant in an ideal flow, an increase in velocity head will cause the total head to:

Increase
Decrease
Remain constant only if another energy term decreases correspondingly
Become zero

Explanation:

Bernoulli’s equation states that the sum of pressure head, velocity head and elevation head remains constant under the ideal assumptions.
Therefore, if elevation and pressure heads are both unchanged, velocity head cannot increase without violating the equation.

Which equation correctly represents Bernoulli’s equation between two points 1 and 2 for ideal steady flow?

p₁/ρg + V₁²/g + z₁ = p₂/ρg + V₂²/g + z₂
p₁/ρg + V₁²/2g + z₁ = p₂/ρg + V₂²/2g + z₂
p₁/ρ + V₁²/2 + z₁ = p₂/ρ + V₂²/2 + z₂
p₁/ρg + V₁²/2 + gz₁ = p₂/ρg + V₂²/2 + gz₂

Explanation:

The correct head form is:
p₁/ρg + V₁²/2g + z₁ = p₂/ρg + V₂²/2g + z₂
All three terms have the dimension of length.

Water flows through a pipe at a velocity of 10 m/s. What is its velocity head approximately? Take g = 9.81 m/s².

2.55 m
5.10 m
10.20 m
20.40 m

Explanation:

Velocity head = V²/2g.
= 10²/(2 × 9.81) = 100/19.62 ≈ 5.10 m.

Water flows through a horizontal pipe whose diameter decreases from 200 mm to 100 mm. If the velocity at the 200 mm section is 2 m/s, what is the ideal velocity at the 100 mm section?

2 m/s
4 m/s
8 m/s
16 m/s

Explanation:

For incompressible flow, A₁V₁ = A₂V₂.
Since area is proportional to diameter squared:
V₂ = (D₁/D₂)²V₁ = (200/100)² × 2 = 8 m/s.

For a horizontal ideal fluid flow through a constant-area pipe, the pressure difference between two sections is:

Always positive
Always negative
Zero
Infinite

Explanation:

In a constant-area pipe carrying steady incompressible flow, velocity remains constant.
For a horizontal ideal flow, elevation is also constant.
Bernoulli’s equation therefore gives equal static pressures at the two sections.

Which of the following is NOT a basic term in the ideal Bernoulli head equation?

Pressure head
Velocity head
Elevation head
Friction loss head

Explanation:

The ideal Bernoulli equation contains pressure head, velocity head and elevation head.
Friction loss is absent because the ideal-fluid assumption neglects viscosity and associated energy losses.
For real fluid flow, a head-loss term is added to the energy equation.

Which statement about the total head of an ideal fluid is correct?

It consists only of pressure head.
It consists only of velocity head.
It is the sum of pressure head, velocity head and elevation head.
It is always equal to velocity head.

Explanation:

Total head is the total mechanical energy per unit weight of fluid.
It is given by H = p/ρg + V²/2g + z.

Mechanical

Which instrument is commonly used to measure the discharge of liquid flowing through a closed pipe?

Venturimeter
Thermometer
Barometer
Hygrometer

Explanation:

A venturimeter measures the flow rate of a fluid through a pipe by using the pressure difference between the inlet and throat.
It works on the principles of continuity and Bernoulli’s equation.

The basic principle used in a venturimeter is:

Bernoulli’s theorem and continuity equation
Newton’s law of cooling
Archimedes’ principle only
Pascal’s law only

Explanation:

As the fluid enters the reduced-area throat, its velocity increases and its static pressure decreases.
The pressure difference is related to the discharge using Bernoulli’s equation and the continuity equation.

Which section of a venturimeter has the minimum cross-sectional area?

Throat
Inlet
Outlet pipe
Diffuser inlet only

Explanation:

The throat is the section of minimum area in a venturimeter.
Velocity is maximum and static pressure is minimum at the throat, subject to losses.

When water flows through a venturimeter, the velocity at the throat is generally:

Greater than the velocity at the inlet
Always zero
Less than the inlet velocity
Exactly equal to the inlet velocity in every case

Explanation:

From the continuity equation, Q = AV.
Since the throat area is smaller than the inlet area, the velocity at the throat increases for steady incompressible flow.

According to Bernoulli’s principle, when the velocity of an ideal incompressible fluid increases, its static pressure generally:

Decreases
Increases proportionally
Remains unchanged in all cases
Becomes atmospheric

Explanation:

For steady, incompressible, frictionless flow at the same elevation, an increase in velocity head is accompanied by a decrease in static pressure head.
This pressure difference is utilized in flow-measuring devices such as venturimeters.

The pressure difference in a venturimeter is generally measured between:

Inlet and throat
Two points in the straight pipe far upstream
Only the outlet and atmosphere
Two points on the diffuser outlet

Explanation:

Pressure taps are commonly provided at the inlet section and throat.
The pressure difference between these locations is used to determine discharge.

The coefficient of discharge of a venturimeter is defined as:

Actual discharge divided by theoretical discharge
Theoretical discharge divided by actual discharge
Pressure head divided by velocity head
Velocity divided by pressure

Explanation:

Coefficient of discharge is:
C_d = Q_actual / Q_theoretical.
It accounts mainly for losses and deviations from ideal flow.

For an ideal venturimeter, the coefficient of discharge is:

1
0
Less than 0
Greater than 10

Explanation:

For ideal flow with no losses, actual discharge equals theoretical discharge.
Therefore, C_d = 1.
Actual venturimeters have C_d values slightly below unity.

The convergent portion of a venturimeter is used to:

Increase fluid velocity and reduce static pressure
Decrease velocity and increase pressure only
Stop the fluid flow
Measure temperature

Explanation:

The converging section reduces the flow area.
For steady incompressible flow, velocity increases as area decreases.
Consequently, static pressure decreases according to Bernoulli’s equation, subject to elevation and losses.

The diffuser portion of a venturimeter is provided mainly to:

Recover pressure by reducing velocity gradually
Increase velocity indefinitely
Increase friction deliberately
Stop the flow

Explanation:

The diffuser is the gradually expanding section after the throat.
It converts part of the kinetic energy back into pressure energy.
A gradual expansion helps minimize flow separation and energy losses.

Why is the diffuser angle of a venturimeter kept relatively small?

To reduce flow separation and energy loss
To increase turbulence intentionally
To reduce the throat velocity to zero
To increase fluid viscosity

Explanation:

A sudden or excessively rapid expansion can cause flow separation.
Flow separation increases energy loss.
A gradual diffuser provides better pressure recovery.

Which flow-measuring device generally has comparatively low permanent head loss?

Venturimeter
Orifice meter
Sudden expansion
Sharp-edged obstruction

Explanation:

A well-designed venturimeter has relatively low permanent pressure loss because the diffuser allows substantial pressure recovery.
This is one of its major advantages over an orifice meter.

Which flow meter is generally cheaper and more compact than a venturimeter?

Orifice meter
Pitot tube
Large venturi tube
Rotameter only

Explanation:

An orifice meter consists of a relatively simple thin plate with an opening installed between flanges.
It is compact and inexpensive but causes a larger permanent pressure loss than a venturimeter.

An orifice meter measures flow rate mainly by measuring:

Pressure difference across an orifice plate
Temperature difference only
Fluid density only
Pipe wall thickness

Explanation:

An orifice plate creates a restriction in the pipe.
The restriction causes a change in velocity and pressure.
The measured pressure difference is related to flow rate using the appropriate discharge equation and coefficient of discharge.

Which of the following is an important disadvantage of an orifice meter compared with a venturimeter?

Higher permanent head loss
Very high installation cost
Very large physical size
No pressure difference is produced

Explanation:

The abrupt contraction and subsequent flow expansion around an orifice plate cause considerable energy loss.
Therefore, its permanent pressure loss is generally higher than that of a venturimeter.
Its low cost and compactness are important advantages.

What is the primary purpose of an orifice plate in an orifice meter?

To create a known restriction and pressure drop in the flow
To eliminate all turbulence
To increase pipe diameter
To measure fluid temperature

Explanation:

The orifice plate has a precisely machined opening.
The restriction changes the flow velocity and pressure, producing a measurable differential pressure.
This pressure difference is used to calculate the discharge.

The discharge through an ideal differential-pressure flow meter is approximately proportional to:

The square root of the measured pressure difference
The square of pressure difference
The cube of pressure difference
The inverse of pressure difference

Explanation:

For incompressible flow through devices such as venturimeters and orifice meters, the theoretical discharge has the general relationship Q ∝ √Δp.
The exact equation also depends on areas, density and the coefficient of discharge.

Which instrument measures local fluid velocity rather than directly measuring the total pipe discharge?

Pitot tube
Venturimeter
Orifice meter
Weir only

Explanation:

A Pitot tube measures the local flow velocity at its measurement point.
Velocity is determined from the difference between stagnation pressure and static pressure.
To determine total discharge in a pipe, the velocity distribution across the section must be considered or an appropriate calibrated arrangement must be used.

The working principle of a Pitot tube is based mainly on:

Conversion of kinetic energy into pressure energy at a stagnation point
Archimedes’ principle
Pascal’s law only
Heat conduction

Explanation:

At the stagnation point, the fluid velocity is reduced to zero.
The kinetic energy associated with the flow is converted into pressure head.
The difference between stagnation and static pressure gives the velocity head.

For an ideal Pitot tube, the velocity of flow is given by:

V = √[2(p₀ − p)/(ρ)]
V = (p₀ − p)ρ/2
V = 2ρ(p₀ − p)
V = ρ/[2(p₀ − p)]

Explanation:

Applying Bernoulli’s equation between the flowing point and the stagnation point gives:
p₀ − p = ρV²/2.
Therefore, V = √[2(p₀ − p)/ρ].
For a real Pitot tube, a velocity coefficient may be included.

At the stagnation point of a Pitot tube, the fluid velocity is:

Zero
Maximum
Equal to the average pipe velocity
Infinite

Explanation:

The stagnation point is a point where the local fluid velocity becomes zero.
The kinetic energy is converted into pressure energy, producing stagnation pressure.

The pressure measured by a Pitot tube at the stagnation point is called:

Stagnation pressure
Vacuum pressure
Vapour pressure
Critical pressure

Explanation:

Stagnation pressure is the pressure obtained when the flowing fluid is brought to rest isentropically in the ideal case.
The difference between stagnation pressure and static pressure is related to the velocity head.

A Pitot-static tube measures:

Static pressure and stagnation pressure
Temperature and density only
Viscosity and density only
Discharge and temperature directly

Explanation:

A Pitot-static tube has openings arranged to sense both static and stagnation pressures.
Their difference provides the velocity head.
It is commonly used for measuring airspeed and local fluid velocity.

For a Pitot tube, if the difference between stagnation and static pressure increases, the flow velocity:

Increases
Decreases
Becomes zero
Remains unchanged in all cases

Explanation:

For incompressible ideal flow:
p₀ − p = ρV²/2.
Therefore, a larger pressure difference corresponds to a higher velocity.

Which flow-measuring device is based on the measurement of stagnation pressure?

Pitot tube
Orifice meter
Venturimeter
Rotameter

Explanation:

A Pitot tube determines velocity using stagnation pressure.
Venturimeters and orifice meters determine flow rate using pressure differences created by area restrictions.

Which device causes the greatest permanent pressure loss among a well-designed venturimeter and an orifice meter for comparable measurement duty?

Orifice meter
Venturimeter
Both always have exactly the same loss
Neither causes any loss

Explanation:

An orifice meter causes significant irreversible losses due to flow separation and turbulence downstream of the restriction.
A venturimeter has a gradual expansion section that recovers much of the pressure.

Which device generally requires the shortest straight length and is suitable for point velocity measurement?

Pitot tube
Venturimeter
Orifice meter
Large nozzle meter

Explanation:

A Pitot tube is a local velocity-measuring instrument.
It is inserted into the flow and aligned with the local flow direction.
It does not require a long converging and diverging body like a venturimeter.

Which equation represents the continuity principle for steady incompressible flow?

Q = AV
Q = A/V
Q = V/A
Q = A + V

Explanation:

For steady incompressible flow, discharge Q equals cross-sectional area A multiplied by mean velocity V.
Thus, Q = AV.
This principle explains the increase in velocity when the flow area decreases in a venturimeter.

If the pipe area is reduced to half while discharge remains constant, the average velocity will:

Double
Become half
Remain unchanged
Become four times

Explanation:

From Q = AV, for constant Q, velocity is inversely proportional to area.
If A becomes A/2, then V becomes 2V.

Which quantity is directly measured by a differential-pressure manometer connected across a venturimeter?

Pressure difference
Discharge directly
Velocity directly
Pipe diameter directly

Explanation:

A differential manometer measures the pressure difference between two pressure taps.
The pressure difference is then used with the venturimeter geometry and fluid properties to calculate discharge.

If the pressure difference across a venturimeter increases, the measured flow rate generally:

Increases
Decreases
Becomes zero
Remains exactly constant regardless of pressure difference

Explanation:

For a given venturimeter and fluid, Q is approximately proportional to √Δp.
Therefore, an increase in differential pressure corresponds to an increase in discharge.

Which flow meter is most suitable when low permanent head loss is an important consideration?

Venturimeter
Orifice meter
Sharp-edged restriction only
Sudden contraction

Explanation:

The venturimeter has a smooth converging section and gradual diffuser.
This design provides relatively good pressure recovery and low permanent head loss compared with an orifice meter.

Which flow meter is generally preferred when low initial cost and compact construction are important?

Orifice meter
Venturimeter
Long-throat venturi only
Large open channel weir

Explanation:

An orifice meter is relatively simple, compact and inexpensive to install.
Its disadvantage is comparatively high permanent pressure loss.

Which instrument can be used to determine the velocity profile at different locations across a pipe cross-section?

Pitot tube
Orifice plate alone
Venturimeter alone
Pressure relief valve

Explanation:

A Pitot tube can be positioned at different points across a pipe section to measure local velocity.
The resulting measurements can be used to study the velocity distribution.

What is the main limitation of using a simple Pitot tube for measuring total discharge in a pipe?

It measures local velocity rather than the average velocity directly
It cannot measure velocity
It always causes complete blockage
It measures only temperature

Explanation:

A simple Pitot tube gives the velocity at its measurement location.
Since velocity varies across a pipe section, multiple measurements or suitable integration/calibration may be required to determine total discharge accurately.

Which statement about a venturimeter is correct?

It has a converging section, throat and diverging section
It consists only of a sharp-edged plate
It has no pressure taps
It works only with gases

Explanation:

A conventional venturimeter consists of a converging cone, throat and diverging cone.
Pressure taps are generally provided at the inlet and throat.
It can be used for liquids and gases with appropriate analysis and design.

Which statement about an orifice meter is correct?

It uses a thin plate with a precisely sized opening to create a pressure drop
It has a long diffuser for complete pressure recovery
It measures only temperature
It requires an impeller

Explanation:

An orifice meter uses an orifice plate installed in a pipe.
The restriction creates a differential pressure related to flow rate.
Compared with a venturimeter, it is simpler and cheaper but generally has greater permanent energy loss.

Which three instruments are commonly based on fluid-flow principles for measuring velocity or discharge?

Venturimeter, Pitot tube and orifice meter
Thermometer, barometer and hygrometer
Lathe, milling machine and shaper
Boiler, condenser and turbine

Explanation:

Venturimeter and orifice meter use differential pressure generated by a restriction to determine flow rate.
A Pitot tube uses stagnation and static pressure to determine local velocity.
All three are important fluid-mechanics instruments for flow measurement.

Mechanical

A hydraulic turbine is a machine that converts hydraulic energy into:

Mechanical energy
Electrical energy directly
Chemical energy
Thermal energy

Explanation:

A hydraulic turbine extracts energy from flowing or falling water and converts it into mechanical shaft power.
The mechanical power can then be used to drive an electrical generator.

Hydraulic turbines are broadly classified according to the energy available at the runner inlet as:

Impulse and reaction turbines
Reciprocating and rotary turbines
Positive and negative turbines
Open and closed turbines only

Explanation:

In an impulse turbine, the available hydraulic energy is converted largely into kinetic energy before water strikes the runner.
In a reaction turbine, water pressure changes while flowing through the runner in addition to changes in velocity.

Which turbine operates mainly by converting the available head into a high-velocity jet before water strikes the runner?

Impulse turbine
Reaction turbine
Centrifugal pump
Reciprocating pump

Explanation:

In an impulse turbine, the nozzle converts pressure/head energy into kinetic energy.
The high-velocity jet then strikes the runner buckets and transfers momentum to the runner.
Pelton turbine is the standard example.

Which of the following is an impulse hydraulic turbine?

Pelton turbine
Francis turbine
Kaplan turbine
Propeller turbine

Explanation:

The Pelton turbine is an impulse turbine.
It is generally used for high-head and relatively low-flow applications.
Francis and Kaplan turbines are reaction turbines.

Which of the following is a reaction turbine?

Francis turbine
Pelton turbine
Turgo impulse turbine
Cross-flow impulse turbine

Explanation:

Francis turbine is a reaction turbine.
It is commonly used for medium-head applications, although its practical operating range is broad.
Water undergoes pressure and velocity changes while passing through the runner.

Which hydraulic turbine is commonly used for low-head and high-flow applications?

Kaplan turbine
Pelton turbine
Impulse turbine only
Reciprocating turbine

Explanation:

Kaplan turbine is an axial-flow reaction turbine.
It is well suited to low-head, high-flow conditions.
Its runner blades are adjustable in many designs, allowing efficient operation over varying loads.

Which hydraulic turbine is generally suitable for high-head applications?

Pelton turbine
Kaplan turbine
Propeller turbine
Francis turbine only

Explanation:

Pelton turbines are particularly suitable for high heads and relatively low flow rates.
Water is converted into a high-velocity jet by a nozzle before entering the runner.

Francis turbine is generally classified as a:

Mixed-flow reaction turbine
Pure impulse turbine
Axial-flow impulse turbine
Positive-displacement turbine

Explanation:

Francis turbine is a reaction turbine with mixed flow through the runner.
Water generally enters the runner radially or approximately radially and leaves approximately axially.

Kaplan turbine is generally classified as a:

Axial-flow reaction turbine
Radial-flow impulse turbine
Mixed-flow impulse turbine
Positive-displacement turbine

Explanation:

Kaplan turbine is an axial-flow reaction turbine.
Water flows substantially parallel to the shaft through the runner.
It is suitable for low-head, high-flow installations.

In an impulse turbine, the pressure across the runner is ideally:

Approximately constant
Continuously increased
Continuously decreased due to reaction effect
Zero everywhere

Explanation:

In an ideal impulse turbine, pressure energy is converted into kinetic energy before the water reaches the runner.
The runner primarily extracts kinetic energy from the jet.
Therefore, there is ideally no significant pressure drop across the runner itself.

In a reaction turbine, the pressure of water across the runner:

Changes as water passes through the runner
Remains exactly constant
Becomes atmospheric at every point
Always increases

Explanation:

Pressure changes through the runner are an important characteristic of reaction turbines.
Both pressure and velocity changes contribute to energy transfer.

Which component converts pressure energy of water into kinetic energy in an impulse turbine?

Nozzle
Draft tube
Runner casing
Tailrace

Explanation:

The nozzle converts the available pressure/head energy into kinetic energy and produces a high-velocity jet.
The jet then transfers momentum to the runner buckets.

The main function of buckets in a Pelton turbine is to:

Receive the high-velocity jet and change its momentum
Increase water pressure
Act as a draft tube
Store water permanently

Explanation:

Pelton buckets are shaped to deflect the incoming water jet substantially.
The change in momentum produces a force on the buckets and consequently torque on the runner.

The characteristic bucket shape of a Pelton turbine is approximately:

Double-cupped with a central splitter
Flat rectangular plate
Helical screw
Cylindrical piston

Explanation:

Pelton buckets are approximately double-cupped and have a splitter at the center.
The splitter divides the incoming jet into two streams flowing over the bucket surfaces.

What is the main function of a draft tube in a reaction turbine?

To recover kinetic energy at the runner exit and permit the turbine to be located above the tailwater
To convert water into steam
To increase runner inlet pressure by combustion
To supply fuel to the turbine

Explanation:

A draft tube is fitted at the outlet of a reaction turbine.
It gradually enlarges, reducing flow velocity and recovering part of the kinetic energy as pressure energy.
It also allows the turbine runner to be located above the tailwater level.

Cavitation in a hydraulic turbine is mainly caused when local pressure falls:

Below the vapour pressure of water
Above atmospheric pressure
Above the critical pressure of steel
Exactly equal to reservoir pressure

Explanation:

When local pressure falls below the vapour pressure, vapour bubbles can form.
When these bubbles move to higher-pressure regions, they collapse and can cause noise, vibration, erosion and performance loss.

Which parameter is commonly used to classify hydraulic turbines for selection according to head, speed and discharge conditions?

Specific speed
Specific gravity only
Absolute viscosity only
Density only

Explanation:

Specific speed is a useful parameter for comparing turbine types and selecting a suitable turbine for given head and power conditions.
Pelton, Francis and Kaplan turbines occupy different practical specific-speed ranges.

A hydraulic turbine primarily operates by extracting energy from:

Water flow
Fuel combustion
Compressed air only
Steam condensation only

Explanation:

Hydraulic turbines use the hydraulic energy of water.
The available energy may be associated with elevation head, pressure head and velocity head.

Which turbine generally has adjustable runner blades?

Kaplan turbine
Pelton turbine
Simple Francis turbine only
Cross-flow impulse turbine

Explanation:

Kaplan turbines commonly use adjustable-pitch runner blades.
Many Kaplan turbines also have adjustable guide vanes.
This arrangement provides good efficiency over a range of flow rates.

A centrifugal pump converts mechanical energy supplied to its shaft primarily into:

Hydraulic energy of the fluid
Electrical energy directly
Chemical energy
Nuclear energy

Explanation:

A centrifugal pump receives mechanical shaft power from a motor or engine.
The impeller transfers energy to the fluid, increasing its velocity and pressure/head.

A centrifugal pump is classified as a:

Rotodynamic pump
Positive-displacement pump
Reciprocating pump
Steam turbine

Explanation:

Centrifugal pumps are rotodynamic pumps.
They continuously transfer energy to the fluid through a rotating impeller.
Reciprocating and rotary pumps such as gear pumps are positive-displacement pumps.

The main rotating component of a centrifugal pump that imparts energy to the fluid is the:

Impeller
Volute casing only
Foot valve
Delivery pipe

Explanation:

The impeller rotates and transfers mechanical energy to the liquid.
The liquid gains velocity and pressure/head as it passes through the pump.

According to the direction of flow through the impeller, centrifugal pumps may be classified as:

Radial-flow, mixed-flow and axial-flow pumps
Hot and cold pumps only
Gas and liquid pumps only
Metal and non-metal pumps only

Explanation:

Radial-flow pumps discharge fluid approximately perpendicular to the shaft.
Mixed-flow pumps have both radial and axial components.
Axial-flow pumps discharge approximately parallel to the shaft.

In a radial-flow centrifugal pump, the fluid generally leaves the impeller:

In a direction approximately perpendicular to the shaft
Exactly parallel to the shaft
Without changing direction
Only downward

Explanation:

In radial-flow pumps, the major component of discharge velocity is radial.
These pumps are commonly used where relatively higher heads are required.

A centrifugal pump having several impellers arranged in series is called a:

Multistage pump
Single-stage pump
Reciprocating pump
Jet pump

Explanation:

In a multistage centrifugal pump, multiple impellers are arranged in series.
The head developed by the stages adds approximately, subject to losses and design conditions.
Such pumps are used where high heads are required.

When several impellers are arranged in parallel, the primary purpose is to increase:

Discharge capacity
Fluid viscosity
Pipe roughness
Specific gravity of the liquid

Explanation:

Parallel pump arrangements increase the flow capacity while operating approximately at the same head.
Series arrangement is generally used to obtain higher head.

What is the basic working principle of a centrifugal pump?

The rotating impeller imparts kinetic energy to the liquid, which is partly converted into pressure energy
The liquid is compressed by a piston
The liquid is heated until it becomes steam
The liquid is moved only by gravity

Explanation:

The impeller increases the velocity and energy of the liquid.
The casing or diffuser converts a portion of the velocity head into pressure head.
This enables the pump to deliver liquid at the required head.

Why is priming required in a conventional centrifugal pump before starting?

To remove air from the pump casing and suction line and fill them with liquid
To increase the motor speed
To lubricate the delivery pipe
To reduce atmospheric pressure

Explanation:

A conventional centrifugal pump generally cannot develop the required suction action if air occupies the casing and suction line.
Priming fills the pump and suction line with the liquid to be pumped.
Self-priming designs use special arrangements to reduce the need for manual priming.

Which component is commonly provided at the lower end of the suction pipe to prevent reverse flow when the pump stops?

Foot valve
Delivery valve
Pressure gauge
Air vessel

Explanation:

A foot valve is a non-return valve fitted near the lower end of the suction pipe in many conventional installations.
It helps retain liquid in the suction pipe and pump casing after stopping.

The function of the volute casing in a centrifugal pump is mainly to:

Collect the liquid from the impeller and convert part of velocity head into pressure head
Supply fuel to the motor
Prevent all rotation of the impeller
Heat the liquid

Explanation:

The volute casing has an increasing cross-sectional area around the impeller.
As flow velocity decreases, part of the kinetic energy is converted into pressure energy.
A diffuser casing performs a similar energy-conversion function using diffuser passages.

Which quantity represents the energy supplied by the pump to the liquid per unit weight?

Pump head
Specific gravity
Viscosity
Displacement

Explanation:

Pump head is commonly expressed in metres of liquid and represents energy per unit weight.
It is related to the increase in total head of the liquid across the pump.

What happens to the theoretical head developed by a centrifugal pump when the impeller speed increases, under similar conditions?

It generally increases approximately with the square of speed
It always decreases with speed
It remains exactly constant
It becomes zero

Explanation:

According to the affinity laws for geometrically similar operation with the same impeller diameter, head varies approximately as N².
Discharge varies approximately as N and power approximately as N³, subject to the usual similarity assumptions.

According to the affinity laws, the discharge of a centrifugal pump varies approximately with:

Speed N
N²
N³
1/N²

Explanation:

For the same impeller diameter and similar operating conditions:
Q ∝ N
H ∝ N²
P ∝ N³

According to the affinity laws, the power required by a centrifugal pump varies approximately with:

Explanation:

For similar operation with unchanged impeller diameter, pump power varies approximately as the cube of rotational speed.
Therefore, even a moderate increase in speed can cause a significant increase in power requirement.

Which curve represents the relationship between pump head and discharge for a particular pump at constant speed?

Head-discharge characteristic curve
Temperature-entropy curve
Stress-strain curve
Load-extension curve

Explanation:

The pump characteristic curve generally plots head developed against discharge at a specified speed.
Other important pump performance curves include efficiency versus discharge and power versus discharge.

The operating point of a centrifugal pump in a piping system is determined by the intersection of:

Pump characteristic curve and system resistance curve
Temperature and entropy curves
Stress and strain curves
Torque and angular displacement curves

Explanation:

The pump supplies head according to its characteristic curve.
The piping system requires a head that depends on static head and flow-dependent losses.
The intersection of the two curves determines the operating discharge and head.

What is pump efficiency?

Ratio of useful hydraulic power delivered to the power supplied to the pump
Ratio of input power to hydraulic power
Ratio of discharge to pressure
Ratio of speed to head

Explanation:

Pump overall efficiency can be expressed as:
η = Hydraulic power / Shaft power
Hydraulic power is commonly represented by ρgQH.

The hydraulic power delivered by a pump to a liquid is given by:

ρgQH
ρQ/H
gH/Q
Q/(ρgH)

Explanation:

Hydraulic power = ρgQH.
Here, ρ is liquid density, g is gravitational acceleration, Q is discharge and H is pump head.
When ρ is in kg/m³, Q in m³/s and H in m, the result is in watts.

What is the manometric efficiency of a centrifugal pump?

Ratio of manometric head to theoretical head imparted by the impeller
Ratio of shaft power to discharge
Ratio of suction pressure to atmospheric pressure
Ratio of actual discharge to theoretical discharge only

Explanation:

Manometric efficiency compares the actual head developed by the pump with the theoretical head imparted by the impeller.
It accounts for hydraulic effects and losses between the impeller and pump delivery.

What is mechanical efficiency of a centrifugal pump?

Ratio of power transferred to the fluid by the impeller to shaft power supplied
Ratio of discharge to head
Ratio of suction head to delivery head
Ratio of hydraulic power to discharge only

Explanation:

Mechanical efficiency accounts mainly for mechanical losses such as bearing, seal and disc-friction losses.
It compares the power actually transferred by the impeller to the fluid with the shaft power supplied to the pump.

What is volumetric efficiency of a centrifugal pump?

Ratio of actual discharge to theoretical discharge
Ratio of shaft power to hydraulic power
Ratio of head to speed
Ratio of pressure to density

Explanation:

Volumetric efficiency accounts for leakage and other effects that cause the actual discharge to differ from the theoretical discharge.
It is generally expressed as actual discharge divided by theoretical discharge.

Cavitation in a centrifugal pump occurs when the local absolute pressure falls:

Below the vapour pressure of the liquid
Above atmospheric pressure
Above delivery pressure
Exactly equal to atmospheric pressure

Explanation:

If local pressure falls below the liquid vapour pressure, vapour bubbles form.
The bubbles can collapse when they reach higher-pressure regions, causing noise, vibration, erosion and reduction in pump performance.

Which parameter is particularly important for assessing the tendency of a centrifugal pump installation to cavitate?

Net Positive Suction Head (NPSH)
Brake power only
Specific gravity only
Discharge pipe diameter only

Explanation:

NPSH describes the suction-side pressure head available above the liquid vapour pressure.
For satisfactory operation, NPSH available should be greater than the NPSH required by the pump, with an appropriate margin.

Which condition generally increases the possibility of cavitation in a centrifugal pump?

Low suction pressure
Higher suction pressure
Lower liquid temperature in all cases
Reduced pump speed in every situation

Explanation:

Low suction pressure reduces the margin between local absolute pressure and vapour pressure.
High liquid temperature also tends to increase vapour pressure and can increase cavitation risk.
Proper suction design and adequate NPSH are essential.

Which arrangement is generally used when a high head is required from centrifugal pumps?

Pumps in series
Pumps in parallel only
Open suction pipe only
Single impeller removed

Explanation:

When pumps are connected in series, their heads approximately add at a given flow, subject to system and pump characteristics.
Parallel pumps are generally used to increase the available discharge.

When centrifugal pumps are connected in parallel, the main objective is to obtain:

Higher discharge capacity
Higher fluid density
Lower liquid temperature
Zero suction head

Explanation:

Parallel operation combines the flow contributions of the pumps.
It is useful when the system requires a larger flow rate than one pump can provide.

Which component controls the flow in many centrifugal pump delivery systems?

Delivery valve
Foot valve
Impeller eye
Bearings

Explanation:

The delivery valve can be used to regulate the discharge from the pump.
During normal operation, the system operating point depends on the pump and system characteristics.

The power transmitted to the fluid by a centrifugal pump is directly proportional to:

ρgQH
ρg/(QH)
Q/(ρgH)
H/(ρgQ)

Explanation:

Hydraulic power is P_h = ρgQH.
Therefore, for a given liquid, increasing discharge or pump head increases the hydraulic power delivered to the fluid.

Which statement correctly compares impulse and reaction hydraulic turbines?

Impulse turbines use a jet with negligible pressure change through the runner, while reaction turbines have pressure change through the runner
Both always have identical pressure behavior
Reaction turbines never use guide vanes
Impulse turbines always require a draft tube

Explanation:

In an impulse turbine, most of the pressure/head energy is converted into jet velocity before the runner.
In a reaction turbine, the runner experiences a pressure change as well as a velocity change.
Draft tubes are associated with reaction turbines, not conventional Pelton impulse turbines.

Which turbine-pump pair is correctly matched?

Pelton — impulse turbine; Kaplan — axial-flow reaction turbine
Pelton — reaction turbine; Kaplan — impulse turbine
Francis — impulse turbine; Pelton — axial reaction turbine
Kaplan — reciprocating turbine; Pelton — centrifugal pump

Explanation:

Pelton is an impulse turbine.
Francis is a mixed-flow reaction turbine.
Kaplan is an axial-flow reaction turbine.
These classifications are important for turbine selection based on head and flow conditions.