RRB JE Mechanical-Metrology Questionbank 2

Mechanical-Engineering

Which of the following is not correct for mechanical comparators? (RRB Mumbai JE 05.10.2008)

They are robust, compact and easy to handle
They have a linear scale, for easy understanding
They don’t require any external supply of electricity or air
They are more expensive as compared to other amplifying devices

Explanation:

Mechanical comparators are cheaper as compared to other amplifying devices. They don’t require external supply, have linear scale, are robust, compact, and portable.

Reed comparator is a ____ comparator. (RRB Malda SSE 25.10.2009)

pneumatics
mechanical
electrical
electro-mechanical

Explanation:

Reed comparator is a type of mechanical comparator used for magnifying small motions of the spindle where amplification obtained is less than 100.

Mechanical comparators usually have a ____ scale. (RRB Mumbai C&G SSE 25.10.2009)

fluctuating
linear
vernier
non-linear

Explanation:

Mechanical comparators usually have a linear scale. Magnification is obtained by mechanical linkages such as rack and pinion, cam and gear train, lever with toothed sector, compound lever, and twisted strip.

____ comparator has got a bold scale and large indicator pointer. (RRB Bhopal TM SSE 25.10.2009)

Electrical
Mechanical
Sigma
Optical

Explanation:

Sigma comparator is a type of mechanical comparator used to magnify small readings into very larger scale. It has got a bold scale and larger indicator pointer.

A comparator for its working depends on —-? (RRB Bangalore SSE 09.09.2012)

Accurately calibrated scale
Comparison with standard such as slip gauges
Accurate micrometer gauge
Optical devices

Explanation:

Comparator is an indirect type of instrument where a known dimension is compared with a working standard (usually slip gauges) and difference in dimension is measured.

The instrument used for comparing the dimensions of a component with a standard length is called —-? (RRB Gorakhpur Design SSE 09.09.2012)

Scale
Vernier calliper
Comparator
Micrometer

Explanation:

Comparator is the instrument used for comparing the dimensions of a component with a standard length.

Which of the following is true for uses of comparators? (RRB Chandigarh SSE 09.09.2012)

Can’t be used in mass production
Not suitable for inspection purposes
Can be used as working gauge
Slow rate of working

Explanation:

Uses of comparators include laboratory standards, working gauges, final inspection gauges, receiving inspection gauges, and checking newly purchased gauges. They are used in mass production at very faster rate.

What is the principle of The Johansson Mikrokator? (RRB Bhubneshwar JE II 29.11.2008) RRB Jammu Section Engg., 2013

Button spinning on a loop of string
Principle of interference
Optical magnification
Principle of transformer

Explanation:

Johansson Mikrokator is a mechanical comparator that works on the principle of a button spinning on a loop of string to obtain mechanical magnification.

Some substances generate voltage when they are subjected to mechanical forces or stresses along specific planes. Such substances are known as —-? (RRB Jammu SSE 09.09.2012)

thermo-electric
magneto-electric
piezo-electric
photo-electric

Explanation:

Piezoelectric effect is the ability of certain materials to generate an electric charge in response to applied mechanical stress, causing shifting of positive and negative charge centers.

From which category ‘Sigma comparator’ belongs? (RRB Bhopal SSE 09.09.2012)

Optical comparator
Mechanical comparator
Mechanical-optical comparator
Pneumatic comparator

Explanation:

Sigma comparator belongs to mechanical comparator category. It is mainly used to measure surface roughness by calculating dimensional difference between measured and standard values with magnification range of 300 to 500.

Working principle of optical comparator —-? (RRB Bangalore SSE 09.09.2012)

Reflection of light
Refraction of light
Interference of light
None of these

Explanation:

Working principle of optical comparator uses reflection of light. It projects magnified image of workpiece on display screen for comparison with standard parameter in a contactless manner.

What is the advantage of mechanical comparator over others? (RRB Bhopal TM SSE 25.10.2009)

Less moving parts
No need of external supply
No error due to parallax
Large range of instrument

Explanation:

Advantages of mechanical comparator: cheaper, no external supply of electricity or air required, linear scale, robust, compact and easy to handle.

Which of the following is true for ‘Cross strip’ in sigma comparator? (RRB Mumbai C&G SSE 25.10.2009)

Has two moving members
Cross strip is hinged
Two members are at 45° to each other
A flexible strip is attached to any one of the members of cross strip

Explanation:

Sigma comparator is a frictionless device for magnifying small motions of a spindle. It consists of cross strip where the hinge consists of a moving component and fixed member connected by flexible strips alternatively at right angle to each other.

Which of the following option is correct regarding the characteristics of comparators? (RRB Gorakhpur RDSO SSE 25.10.2009)

Minimum inertia
Minimum compensation for temperature effect
High measuring pressure
Minimum versatility

Explanation:

Characteristics of comparators: pointer should come rapidly to rest, free from oscillations, free from backlash and unnecessary friction, means for lifting plunger, and minimum inertia.

What is the use of bleed valve in flow type pneumatic comparator? (RRB Chandigarh SSE 25.10.2009)

Zero adjustment
Measurement of size
Connect passage of air from plastic tube to gauging head
Used with pressure reducing unit

Explanation:

Bleed valve in pneumatic comparator is used for zero adjustment. A screw at the inlet of tapered glass tube changes magnification by passing some air supply.

Which of the following is not correct for pneumatic comparator? (Konkan Railway TA 2017)

Independent of operator skill
Loss of accuracy due to gauge wear
Speedy operation
Total life cost is less

Explanation:

In pneumatic comparator, there is no physical contact with setting gauge or part being measured, so there is no loss of accuracy due to gauge wear.

What is the order of magnification in flow type pneumatic gauge? (DMRC JE 2013)

100 to 1000 times
500 to 5000 times
50 to 500 times
100 to 2000 times

Explanation:

Flow type pneumatic gauges have quick response, permit large clearance between object and nozzle, less wear, less air consumption, and magnification of order 500-5000 times is possible.

Which of the following is true for Pneumatic sensitivity in pneumatic comparators? (RRB Mumbai JE 19.12.2010)

Directly proportional to operating pressure
Inversely proportional to operating pressure
Directly proportional to geometrical area of orifice
Independent of area of orifice and operating pressure

Explanation:

Pneumatic sensitivity in pneumatic comparator is directly dependent upon operating pressure and inversely proportional to geometrical area of orifice, represented as dp/dA.

What is the relation between overall magnification and pneumatic sensitivity in pneumatic comparators? (RRB Allahabad JE 19.12.2010)

Independent of each other
Overall magnification is directly dependent on the square of pneumatic sensitivity
Overall magnification is inversely proportional to the pneumatic sensitivity
Overall magnification is directly dependent on the pneumatic sensitivity

Explanation:

Overall magnification is the rate of change of linear movement of pointer to change in dimension (dR/dL) and is directly proportional to pneumatic sensitivity.

Which of the following option is correct for velocity type pneumatic gauge? (BMRCL JE 24 Feb. 2019)

Operate by sensing momentary rate of flow of air
Response speed is less than back pressure type
Low amplification
Filter is placed after pressure reducing unit

Explanation:

Flow (velocity) type pneumatic comparator operates by sensing and indicating momentary rate of airflow, sensed by a glass tube with tapered bore mounted over a graduated scale.

The type of surfaces best suited for measuring surface roughness using a light interference microscope are —-? RRB JE (Re-Exam) 04.06.2025

liquid surfaces
surfaces requiring high-precision 3D mapping
soft or thin surfaces
very large surface areas

Explanation:

Light interference microscopes are best suited for measuring surface roughness on soft or thin surfaces.

To measure surface finish, the two types of stylus instruments used are —-? RRB JE (Re-Exam) 04.06.2025

Digital and Analog
Manual and Automated
True Datum and Surface Datum
Contact and Non-contact

Explanation:

Contact stylus instruments use a physical stylus making direct contact with the surface. Non-contact instruments use optical or other methods like laser or light interferometry.

The function of the supporting column in a Tool Maker’s Microscope is to —-? RRB JE (Re-Exam) 04.06.2025

provide vertical working distance
magnify the image
illuminate the workpiece
hold the specimen in place

Explanation:

The supporting column in a tool maker’s microscope holds the specimen in place. Tool maker’s microscope is a versatile high precision instrument used in metrology and quality control.

The sensing element in the Tomlinson Surface Meter is —-? RRB JE Stage 2 (22.04.2025 9:00 AM-11:00 AM)

the shoe
rollers
the stylus
springs

Explanation:

Tomlinson Surface meter is an instrument used to measure surface roughness with its stylus-based sensing element, widely used in automotive, aerospace, and precision manufacturing.

While measuring surface texture, the part of the profilometer that makes contact with the workpiece surface is —-? RRB JE Stage 2 (22.04.2025 9:00 AM-11:00 AM)

a motorised mechanism
a finely pointed stylus
a recording unit
an electrical pickup

Explanation:

A profilometer uses a diamond stylus probe (typically diamond tip) that moves across the surface. The stylus makes contact with the workpiece surface.

While measuring surface texture, the part of the profilometer that makes contact with the workpiece surface is —-? RRB JE Stage 2 (22.04.2025 2:30-4:30 PM)

a finely pointed stylus
an electrical pickup
a motorised mechanism
a recording unit

Explanation:

Profilometer measures surface texture. The part that makes contact is a finely pointed stylus made of diamond or tungsten carbide.

What is the capability of a profilometer instrument? RRB JE Stage 2 (22.04.2025 2:30-4:30 PM)

Measure surface flaws only
Measure surface roughness only
Measure surface waviness only
Measure roughness together with waviness and any other surface flaws

Explanation:

Profilometer measures roughness together with waviness and any other surface flaws. It traces the surface using a stylus or optical sensor to measure deviation from a reference plane.

Normal ray, incident ray and reflected ray lie in the —-? RRB JE 30-08-2019

Three mutually perpendicular planes
Same plane
Same line
Same point

Explanation:

According to the Law of Reflection, when a ray of light falls upon a plane surface, the incident ray, reflected ray, and normal to the surface at the point of incidence lie in the same plane.

The Tomlinson recorder is associated with the measurement of —-? RRB JE 30-08-2019

Surface perpendicularity
Surface finish
Stiffness
Hardness

Explanation:

Tomlinson recorder is a surface finish measuring instrument based on mechanical-cum-optical magnification method, used for inspecting surface roughness where direct measurement method is preferred.

Merin instrument assesses —-? RRB JE 30-08-2019

Groove depth
Internal diameter
Internal angle
Surface irregularities

Explanation:

Merin instrument assesses surface irregularities through its frictional property and average slope of the irregularities.

Which of the following fits comes under the category of interference fit? RRB JE 30-08-2019

Tight fit
Push fit
Force fit
Shrink fit

Explanation:

Interference fit occurs when the minimum permissible diameter of the shaft is greater than the maximum allowable diameter of the hole. Shrink fit is an example of interference fit.

By using a planimeter which can find out the area of any curve to find? (RRB Mumbai JE 19.12.2010)

CLA value
RMS value
Maximum peak to valley height
Average depth roughness

Explanation:

Planimeter is used to find CLA (Center Line Average) value. Ra = (h₁ + h₂ + h₃ + … + hₙ)/n.

Roughness is referred as —-? (RRB Mumbai SSE 19.12.2010)

Primary texture
Secondary texture
Both (a) & (b)
None of these

Explanation:

Surface roughness is called primary texture and is caused by the action of the cutting tool used to produce the surface.

Waviness is referred as —-? (DMRC JE 2013)

Primary texture
Secondary texture
(a) & (b) both
None of these

Explanation:

Waviness is called secondary texture and is caused by imperfections in the cutting tool machine such as vibration, chatter, heat treatment, or a bodily trued grinding wheel.

Tomlinson recorder is associated with the measurement of —-? (DMRC JE 20.04.2018)

Surface flaws
Surface finish
Surface flatness
Surface perpendicularity

Explanation:

Tomlinson surface meter is a surface finish measuring instrument based on mechanical-cum-optical magnification method.

Which of the following instruments is used to measure smoothness of a metallic surface? (Konkan Railway STA 2017)

Talysurf
Coordinate Measuring Machine
Profile Projector
None of the above

Explanation:

Talysurf is electronic equipment used to measure surface roughness. It works on the carrier modulating principle.

The primary texture or roughness or micro-errors on surface results due to —-? (Konkan Railway TA 2017)

normal action of the tool in production process
vibrations and non-uniformity of cutting process
flaws in material
dominant direction of tool marks (lay)

Explanation:

Primary texture results due to normal action of the tool in production process, caused by action of cutting tool used to produce the surface.

The secondary texture or waviness, or macro-error on surface results due to —-? (RRB Kolkata Diesel JE 25.10.2009)

normal action of the tool in production process
vibrations and non-uniformity of cutting process
flaws in material
dominant direction of tool marks (lay)

Explanation:

Secondary texture results due to vibrations and non-uniformity of cutting process caused by imperfections in the cutting tool machine.

The surface roughness on a drawing is represented by —-? (RRB Jammu JE 25.10.2009)

circles
squares
zig-zag lines
triangles

Explanation:

Surface roughness on a drawing is represented by triangles.

RMS method gives —-? (RRB Mumbai C&G SSE 25.10.2009)

Tolerance
Allowance
Surface roughness
Fit

Explanation:

RMS (Root Mean Square) value is defined as the square root of the mean of squares of the ordinates of the surface measured from a mean line.

Profilometer is an instrument used to measure —-? (RRB Allahabad SSE 09.09.2012)

gear involute
thread profile
taper
surface roughness

Explanation:

Profilometer is used to measure a surface’s profile in order to quantify its roughness. Types include contact and non-contact profilometers.

Which of the following is not the correct method of specifying numerical value of surface roughness? (RRB Kolkata SSE 09.09.2012)

Centre-line average (CLA) value
mean-line and envelop line systems
r.m.s value
peak-to-valley height

Explanation:

Methods of specifying surface roughness include CLA (Ra), RMS value, maximum peak to valley roughness (hmax), and average of five peaks and five valleys.

Figure shows the roughness characteristics of a surface. Distances A and B represent —-? (RRB Bhopal SSE 09.09.2012)

CLA values
peak to valley height
depth of smoothness and mean depth respectively
mean depth and depth of smoothness respectively

Explanation:

Distances A and B represent peak to valley height.

Which of the following not a quantitative method of measuring roughness? (RRB Jammu SSE 09.09.2012)

Intersection method
Interference method
Stylus method
Scratch method

Explanation:

Quantitative methods include intersection method, interference method, and stylus method. Scratch method is a qualitative method.

Which quantitative method used fine needle for irregularity checking? (RRB Bhubneshwar JE II 29.11.2008) RRB Kolkata Apprentice Engg., 14.10.2001

Intersection method
Interference method
Stylus method
Scratch method

Explanation:

Stylus method uses a probe to detect the surface by physically moving a probe along the surface to acquire surface height.

Which of the following is qualitative method of measuring roughness? (RRB Allahabad JE 09.09.2012)

Reflection method
Interference method
Stylus method
Pneumatic measuring method

Explanation:

Qualitative techniques include optical appearance such as reflectivity of a surface or strength of machining lay, as well as dragging a thumbnail across the surface.

The CLA value is associated with —-? (RRB Chandigarh SSE 09.09.2012) (PHED Rajasthan 2015)

fineness of an abrasive for grinding wheel
sharpness of a tool edge
an elastic behaviour of material
surface roughness

Explanation:

CLA (Center Line Average) value is associated with surface roughness.

Surface roughness on a drawing is represented by —-? (RRB SSE Secunderabad Red Paper, 21.12.2014) (RRB JE Ajmer 2014)

circles
squares
triangles
rectangles

Explanation:

Surface roughness on a drawing is represented by triangles with parameters: Ra value, production method, sampling length, direction of lay, and machine allowance.

Which of the following is a common metrological application of interferometry? RRB JE Stage 2 (22.04.2025 2:30-4:30 PM)

Analysing chemical composition
Determining surface hardness
Inspecting machine parts for straightness
Measuring temperature

Explanation:

Interferometry uses interference of light waves to measure small distances, surface irregularities, and refractive index changes. It is extensively used to inspect straightness of machine parts.

The type of lasers commonly used in laser interferometers for metrology applications are —-? RRB JE Stage 2 (22.04.2025 2:30-4:30 PM)

solid-state lasers
dye lasers
gas lasers
excimer lasers

Explanation:

Gas lasers are most commonly used in laser interferometers for metrology due to their stability, coherence, and ability to produce high quality beams.

What is the full form of NPL Gauge interferometer? RRB JE 29-08-2019

Nikon Pulsed Laser
National Physics Laboratory
Nuclear Plasma Laboratory
Nuclear Physics Laboratory

Explanation:

NPL stands for National Physics Laboratory, conceptualized in 1943 by CSIR Governing Body for industrial growth through science and technology.

The process of splitting up of white light into seven constituent colours is called —-? RRB JE 29-08-2019

Interference
Refraction
Dispersion
Photosynthesis

Explanation:

Dispersion is the process of splitting up of white light into seven constituent colours.

Interferometers are used for —-? (RRB Bangalore SSE 09.09.2012)

Measuring flatness
Determining the length of slip gauge
(a) and (b)
None of these

Explanation:

Interferometers are used for measuring flatness and determining the length of slip gauges.

In interferometric method, the path differences between one bright band and the next is varied by —-? (RRB Bhopal TM SSE 25.10.2009) (MPPSC A.E., 2014)

Half wavelength
Two half wavelength
One quarter wavelength
Two wavelength

Explanation:

In interferometric method, the path difference between a bright band and the next is varied by two half wavelengths.

The method of fractional coincidences in interferometric techniques is used for —-? (RRB Mumbai C&G SSE 25.10.2009)

Measurement of end gauges
Flatness of surface
Linear displacement measurement
Convexity/concavity of surfaces

Explanation:

The method of fractional coincidences in interferometric techniques is used for measurement of end gauges.

Working principle of interferometer —-? (RRB Malda SSE 25.10.2009)

Reflection of light
Refraction of light
Polarisation of light
Interference of light

Explanation:

Working principle of interferometer is based on interference of light, where light is split into two beams that travel different optical paths and then combined to produce interference.

Which of the following is the incorrect condition for a perfectly flat surface when tested for interferometry? (RRB Gorakhpur RDSO SSE 25.10.2009)

Monochromatic light is used
Viewing angle should be greater than 0°
Optical flats are important in light wave measurement
For perfect flat surface alternate light and dark bands are observed

Explanation:

Viewing angle should be 0° (line of sight at 90° to reference surface). As this angle increases, it will cause error.

If the angle at which bands are viewed is 30° in flatness testing with interferometry, what is the possible error? (RRB Mumbai C&G JE 25.10.2009)

0%
15%
30%
45%

Explanation:

If viewing angle is 30°, three fringes may be seen as 2.5, causing 15% error. At 45°, error is nearly 40%.

What is the range of the diameter of optical flats? (RRB Chandigarh SSE 25.10.2009)

10 to 50 mm
50 to 100 mm
100 to 200 mm
25 to 300 mm

Explanation:

Optical flats are circular pieces of optical glass with high degree of finish. They vary from 25 to 300 mm in diameter.

In flatness testing with interferometry, if surfaces are perfectly wrung, then which option is correct regarding fringe pattern? (Konkan Railway SSE 2015)

No fringe pattern
Fringes are closer
Fringes are at great distance
Indistinguishable pattern

Explanation:

If surfaces are perfectly wrung together, there will be no air gap between surfaces and no fringe pattern will be observable.

Which of the following is true for quartz flats? (Konkan Railway TA 2017)

Have 200 to 400% more wearing quality than optical flats
Have 10% more wearing quality than optical flats
Have 10% less wearing quality than optical flats
Have 200 to 400% less wearing quality than optical flats

Explanation:

Quartz flats have 200 to 400% more wearing qualities than optical flats with working surfaces finished to high optical degree of flatness.

Which of the following option is incorrect for flatness testing by interferometry? (DMRC JE 20.04.2018)

For checking concave or convex surface optical flat is pressed lightly
If angle between optical flat and work surface reduces, then fringe spacing decreases
For perfectly flat surface condition of complete interference satisfies
Only one point contact between optical flat and surface is possible in some cases

Explanation:

If angle θ reduces, fringe spacing increases; if θ increases, fringe spacing decreases.

If the angle between optical flat and surface to be tested is very small, then what is the difference of separation between optical flat and surface between two similar adjacent fringes? (RRB Mumbai SSE 19.12.2010)

λ
λ/2
λ/3
3λ/2

Explanation:

Change in separation between surface and optical flat between two adjacent and similar fringes is λ/2.

The NPL flatness Interferometer is designed and used for —-? (RRB Chandigarh SSE 25.10.2009)

absolute measurement of length of slip gauges
judging flatness of surface
comparing height with a standard reference
measurement of fringe displacement

Explanation:

NPL flatness interferometer is designed and used for judging flatness of surface. The gauge to be checked is placed on a base plate with high degree of flatness.

What is the pattern of fringes, if an optical flat is resting on any hill? (RRB Allahabad SSE 19.12.2010)

Central band dark
Concentric dark and light band fringes
Straight dark fringes
Central band may be light or black

Explanation:

If optical flat makes contact with hills, it behaves as if placed on convex surface, producing concentric bright and dark fringes with central bright fringe.

Which of the following option is correct for the given statements about interferometry applied to flatness testing? Statement 1: If the angle between optical flat and surface is too large then there will be largely spaced fringe pattern is observed. Statement 2: Quartz flats are very sensitive to heat. (RRB Bhubneshwar JE-II 19.12.2010)

T, T
F, T
T, F
F, F

Explanation:

If angle θ is too large, fringes will be too closely placed as to be indistinguishable. Quartz has minimum expansion due to heat.

Which of the following option is true for optical flats used in flatness testing? (BMRCL JE 24 Feb. 2019)

Type A optical flats has only one surface flat
Optical flats are better than quartz flats
White light source is very important in measurement by light wave interference
Working surfaces of optical flats are cylindrical

Explanation:

Type A optical flats have only one flat surface, indicated by an arrow head on the cylindrical surface pointing towards the working surface.

The NPL gauge Interferometer is designed and used for —-? (JMRC JE 10.06.2017)

absolute measurement of length of slip gauges
judging flatness of surface
comparing height with a standard reference
measurement of fringe displacement

Explanation:

Laser interferometers can be used for measurement of small diameter and large displacement by placing fibre in the beam and projecting interference fringes onto a screen.

Laser interferometers can be used for measurement of —-? (DMRC JE 22.09.2017)

Small diameter
Large displacement
Surface parallelism
(a) and (b)

Explanation:

Laser interferometers can be used for measurement of small diameters as well as large displacement.

The disadvantage of the early shadow projector was that the —-? RRB JE (Re-Exam) 04.06.2025

magnification was insufficient
screen was too far from the operator
image was too small
image was distorted

Explanation:

Disadvantages of early shadow projector: insufficient magnification, limited to inspecting surface profiles, requires proper calibration and alignment, may not be suitable for analyzing material composition.

In a profile projector, the magnified image of the workpiece is created by —-? RRB JE Stage 2 (22.04.2025 9:00 AM-11:00 AM)

projection lens
a Vernier micrometer
mirrors
condenser lens

Explanation:

In profile projector, the magnified image of workpiece is created by projection lens, ensuring clear and accurate image for precise measurement.

In a modern optical measuring microscope, the cross-wires are —-? RRB JE Stage 2 (22.04.2025 9:00 AM-11:00 AM)

located on the objective lens
located on the surface of the work piece
etched on glass within the eyepiece
located on the XY stage

Explanation:

In a modern optical measuring microscope, the cross-wires are etched on glass within the eyepiece.

The primary purpose of a shadow projector is to —-? RRB JE Stage 2 (22.04.2025 2:30-4:30 PM)

produce an undistorted magnified reflected image of an object
detect internal flaws in a material
analyse material composition
measure surface roughness

Explanation:

The primary purpose of a shadow projector (profile projector or shadowgraph) is to project and enlarge the shadow of an object onto a screen for precise inspection and measurement.

How many mirrors are used for magnification in the Zeiss Ultra-Optimeter? RRB JE Stage 2 (22.04.2025 2:30-4:30 PM)

One
Four
Two
Three

Explanation:

Zeiss Ultra-Optimeter uses two mirrors: one objective mirror near the workpiece and one projection mirror receiving the reflected image.

How many types of optical flats are present? RRB JE 29-08-2019

Explanation:

Optical flats have 2 types: Type A (only one surface flat, indicated by arrow) and Type B (both surfaces flat and parallel). Optical flats work on principle of interference of light.

Temperature inversion is a condition in which the temperature of the atmosphere —-? RRB JE 29-08-2019

Always increase with altitude
Remains same
Always decrease with altitude
Either increase or decrease with altitude

Explanation:

Temperature inversion is a condition in which temperature of atmosphere always increases with altitude. Warmer air is held above colder air, trapping air pollution like smog close to ground.

Which of the following is an example of diffuse reflection? RRB JE 31-08-2019

Reflection on mirrors
Both reflection on mirror and still water
Reflection on roadway
Reflection on still water

Explanation:

Reflection on roadway is an example of diffuse reflection where incident ray is reflected at many angles, e.g., bicycle reflectors, paper.

To what degree are the edges of optical flats bevelled? RRB JE 31-08-2019

90°
30°
45°
60°

Explanation:

The edges of optical flats are bevelled at 45°.

Telecentric arrangement used in —-? (RRB Chandigarh SSE 09.09.2012)

Optical profile projector
Tool makers microscope
Interferometer
Collimator

Explanation:

Telecentric arrangements are used in optical profile projector. Telecentric lenses are often used for precision optical two dimensional measurements.

An optical gauge works on the principle of —-? (RRB Bhopal TM SSE 25.10.2009)

reflection of light rays
polarization of light rays
interference of light rays
refraction of light rays

Explanation:

Optical gauge works on the principle of interference of light rays. When two light waves interact, the wave effect leads to interference of light.

Profile of a gear tooth can be checked by —-? (RRB Bhopal SSE 09.09.2012)

Optical projector
Optical pyrometer
Bench micrometer
Sine bar

Explanation:

Profile of gear tooth can be checked by optical projection method using optical comparator and profile projector to magnify and compare with master profile.

Which of the following instruments is the most accurate? (RRB Mumbai JE 19.12.2010)

Micrometer screw gauge
Vernier calliper
Vernier dial gauge
Optical projector

Explanation:

Optical projector is the most accurate instrument as it applies principles of optics to inspection of manufactured parts.

Optical flats are made of —-? (DMRC JE 20.04.2018)

Quartz
Glass
Steel
Plastic

Explanation:

Optical flats are made of quartz. They use monochromatic light to determine flatness of other optical surfaces by interference. Quartz has low coefficient of expansion and much longer useful life.

Figure shows the principle of —-? (RRB Kolkata Diesel JE 25.10.2009)

microscope
telescope
optical clinometer
auto collimator

Explanation:

Auto collimator is an optical instrument for non-contact measurement of small angles, straightness, flatness, squareness, and parallelism.

Optical flats are used in conjunction with —-? (RRB Jammu JE 25.10.2009)

angular measurements
surface flatness
surface parallelism
interferometric measurement

Explanation:

Optical flats are used in conjunction with interferometric measurement. They work on the principle of interference of light.

In the phenomenon of optical interference, the two beams of light, both originating from the same source, can cause interference patterns when the path difference between them amounts to —-? (RRB Bhubneshwar JE-11 19.12.2010)

1 micron
1 mm
one wavelength of the light being used
an odd half-wavelength of the light being used

Explanation:

Two beams of light from the same source cause interference patterns when path difference amounts to one wavelength of light being used.

Which projection method used for inspection of machine parts? (JMRC JE 10.06.2017)

Shadow projection
Profile projection
Orthographic projection
(a) and (b) both

Explanation:

Projection methods used for inspection of machine parts include shadow projection and profile projection.

A collimator is simply a —-? (BMRCL JE 24 Feb. 2019)

source of a bundle of parallel light rays
source of point light
source of alignment telescope
device used in interferometric measurements

Explanation:

Collimator is simply a source of a bundle of parallel light rays, changing diverging light from a point source into a parallel beam for specialized measurements.

Angle Dekkor is another type of —-? (RRB Allahabad SSE 19.12.2010)

auto-collimator
optical square
clinometer
angle gauge

Explanation:

Angle dekkor is a small variation of the auto-collimator, used as a comparator measuring change in angular position of reflector in two planes.

Auto collimator is used for —-? (RRB Mumbai JE 19.12.2010)

Straightness measurement
Parallelism measurement
Flatness measurement
Angular measurement

Explanation:

Auto collimator is used for measurement of small angles with very high sensitivity, including precision alignment, detection of angular movement, and verification of angle standards.

Profile of a gear tooth is to be checked. Which one of the following device would you choose? (DMRC JE 20.04.2018)

optical pyrometer
bench micrometer
sine bar
optical projector

Explanation:

Profile of gear tooth can be checked by optical projector where optical comparator and profile projector magnify the profile for comparison with master profile.

Auto-collimator is used for measurement of —-? (Konkan Railway SSE 2015)

small angular differences
flatness
linear surfaces
concavity

Explanation:

Auto-collimator is used for measurement of small angular differences with very high sensitivity.

Optical square is used in connection with —-? (RRB Mumbai C&G JE 25.10.2009)

alignment tests involving two surfaces at right angles
interferometry measurements
angular measurements
circular division

Explanation:

Optical square is used in connection with alignment tests involving two surfaces at right angles.