Metrology RRB JE Questionbank

Metrology

A feeler gauge is used to check

Radius
Screw pitch
Surface roughness
Thickness of clearance

Explanation:

A feeler gauge is used to check and measure the width of a gap or clearance between two mating parts.

The maximum angle that can be set using sine bar is

15°
45°
30°
60°

Explanation:

Purpose: Precision measurement of angles.
Working principle: Based on trigonometry →
- sinθ= h /L
- where θ = angle, h = height of slip gauges, L = distance between sine bar rollers.
Accuracy: Very high (up to 0.01 mm or 0.01° depending on slip gauge accuracy).
Maximum recommended angle: Up to 45° (beyond that accuracy decreases).
Material: Usually made of high-grade steel, hardened & ground.

Sigma comparator is a

Electrical comparator
Mechanical comparator
Optical comparator
Pneumatic comparator

Explanation:

A Sigma Comparator is a mechanical comparator used for measuring very small deviations (like surface roughness or dimensional differences) between a workpiece and a standard reference.
A comparator is a device that compares an unknown dimension with a standard (master) and shows the difference, not the absolute size.

Which of the following statements is true?

An angle dekkor is a small variation of an autocollimator
An angle dekkor is a small variation of a bevel protactor
An angle dekkor is a small variation of a clinometer
An angle dekkor is a small variation of a sine bar

Explanation:

angle dekkor – variation of the autocollimator.
Optical instrument to measure very small angular deviations / angular differences with high sensitivity.

The closeness with which the reading of an instrument approaches the true value of the variable being measured is called

Accuracy
Precision
Sensitivity
Resolution

Explanation:

Accuracy– Closeness of a measured value to the true or accepted value.
Precision– How closely repeated measurements under the same conditions agree with each other. I.e. consistency or repeatability.
Sensitivity– The change in output of an instrument per unit change in the measured quantity.
Resolution– The smallest increment of the input signal that an instrument can display/detect.

A radius gauge is also known as-

Fillet gauge
Snap gauge
Feeler gauge
Slip gauge

Explanation:

Fillet Gauge/Radius Gauge – Used to measure the radius of curvature (concave & convex radii).
Snap Gauge – A Go–No Go type gauge used for checking external dimensions like shaft diameter.
Feeler Gauge – A set of thin blades used to measure small gaps/clearances between mating parts.
Slip Gauge (Gauge Block) – Precision blocks used for accurate measurement, calibration, and setting of instruments.

To what degree are the edges of optical flats bevelled?

90°
30°
45°
60°

Explanation:

In optical metrology, the edges of optical flats are typically beveled to a 45° angle.
This beveling is achieved through precise grinding and polishing techniques.
The primary purpose of this bevel is to eliminate sharp edges, thereby reducing the risk of chipping and enhancing the durability of the optical flat during handling and usage.

The term grating in metrology means that-

Rulings follow a logarithmic scale
Rulings need not have any pattern
Rulings are more closely spaced, producing a periodic pattern without blank gaps
Rulings are spaced relatively far apart, requiring some type of interpolating device to make accurate settings

Explanation:

Johansson Gauges are otherwise known as-

Slip gauges
Radius gauges
Snap gauges
Feeler gauges

Explanation:

Determine the elevation for 30° using 5.00″ sine bar.

2.5000″
3.8302″
2.8679″
1.7101″

Explanation:

Which of the following is NOT an angular measuring instrument?

Autocollimator
Sinebar
Micrometer
Bevel Protractor

Explanation:

In a vernier caliper, the main scale reads in millimeters with a least count of 0.1 mm. Ten divisions on the vernier correspond to nine divisions of the main scale. Determine the least count of the caliper.

0.01 mm
0.001 mm
0.1 mm
1 mm

Explanation:

Wringing action is a combination of sliding and-

Twisting
Drawing
Rolling
Reciprocating

Explanation:

The preferred instrument for measuring depth of holes, slots and recesses is-

Vernier depth gauge
Feeler gauge
Screw gauge
Vernier caliper

Explanation:

Which of the following comes under the category of random errors?

Errors resulting from friction
Calibration error
Misalignment error
Parallax error

Explanation:

Feeler gauge are used to-

Check and measure the bearing clearance
All of the options
Check and set the spark plug gaps
Check the gap between the mating parts

Explanation:

Where does the bubble rest on the scale when spirit level is placed horizontally?

Centre
Left most
Right most
Bottom

Explanation:

Which of the following is used to check the diameters of holes?

Plug gauge
Fillet gauge
Standard screw pitch gauge
Slip gauge

Explanation:

What is the full form of NPL Gauge interferometer?

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

Explanation:

Which comparator is generally used to measure small displacement of spindles?

Optical comparators
Reed type comparator
Sigma comparator
Electric comparators

Explanation:

Which of the following fits comes under the category of interference fit?

Tight fit
Push fit
Force fit
Shrink fit

Explanation:

How many divisions are graduated on the thimble of micrometer?

Explanation:

Temperature inversion is a condition in which the temperature of the atmosphere-

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

Explanation:

LVDT is a

Pressure transducer
Displacement transducer
Velocity transducer
Acceleration transducer

Explanation:

A vernier scale is good enough to read in after decimal

One digit
Two digits
Three digits
Four digits

Explanation:

A transducer is a device which

Converts one form of power into another
Converts one form of energy into another
Helps in measuring electrical signal
Is similar to a transformer

Explanation:

The ratio of output signal or response of the instrument to a change in input or measured variable is called

Sensitivity
Precision
Resolution
Threshold

Explanation:

Interferometers are used for measurement of

Changes in life cycle processes due to radiation
Effect of interference of wearing of one mechanical component, on the whole machine
Measurement of very small displacements and surface irregularities
Chemical analysis of compounds

Explanation:

Sclerometer is used by

Astronomers
Civil Engineering Surveyors
Doctors
Metallurgists

Explanation:

Clearance between the mating parts is measured using

Dial gauge
Go-gauge
No-go gauge
Feeler gauge

Explanation:

The instrument used to measure external and internal diameter of shafts, thickness of parts and depth of holes is

Inside micrometer
Outside micrometer
Vernier calipers
Slip gauge

Explanation:

A ring gauge is used to

Check the clearance between two mating surfaces
Test the accuracy of holes
Check the diameter of shafts or studs
All of the above

Explanation:

No Go Ring Gauge will have diameter based on ……..diameter of the component.

Minimum tolerance diameter
Maximum tolerance diameter
Nominal diameter
Average diameter

Explanation:

Strain Gauge is used to convert

Force into displacement
Mechanical displacement into change in resistance
Electric current into Mechanical displacement
Sound Energy into Electric Energy

Explanation:

Which one of the following consists of those surface irregularities on the part, which are of considerable wavelength of periodic character?

Lay
Waviness
Roughness
Flaws

Explanation:

Which instrument is most appropriate for measuring the surface roughness of a finely machined component?

Optical profilometer
Micrometer
Dial indicator
Vernier caliper

Explanation:

The smallest measurement that can be recorded accurately with an instrument is called

Least count
Zero error
Precision
Accuracy

Explanation:

Which one of the following is a type of the Dimensioning System?

Elliptic system
Leaders system
Unidirectional system
None of these

Explanation:

GO and NO GO gauge is a type of

Plug gauge
Slip gauge
Ring gauge
Limit gauge

Explanation:

All of the following are typical examples of interference fit, except

Shrunk on couplings
Crank pins
Cross head slides
Iron types

Explanation:

Ring gauge is used to measure

outside diameter but not roundness
roundness but not outside diameter
both outside diameter and roundness
external threads only

Explanation:

The following gauge is used for checking of holes

Plug gauge
Snap gauge
Dial gauge
Ring gauge

Explanation:

If the lower deviation of a hole is zero and the minimum limit of hole size is the basic size, what type of shaft is it?

Basic Hole
Shaft Basis System
Hole Basis System
Basic Shaft

Explanation:

______ is used for profile leveling.

Collinear method
Circular method
Circumferential method
Collimation method

Explanation:

At which of the following angles are strain gauges set in a rectangular strain rosette?

zero, 45, 60
zero, 45, 90
zero, 45, 120
zero, 60, 120

Explanation:

Which of the following is not a metrological feature of pneumatic comparators?

Minimum gauging force
High range amplification
Non-contact inspection of work parts
Rapid response

Explanation:

Which among the following is the measured size of a finished part?

Actual size
Dimensioned size
Production size
Basic size

Explanation:

According to Indian standard specifications, 100 H6g5 means that the

Tolerance grade for the hole is 6 and for the shaft is 5
Tolerance grade for the shaft is 6 and for the hole is 5
Tolerance grade for the shaft is 4 to 8 and for the hole is 3 to 7
Tolerance grade for the hole is 4 to 8 and for the shaft is 3 to 7

Explanation:

In a hole basis system, the fundamental deviation for the hole is

0 mm
0.8 microns
0.01 mm
0.01 microns

Explanation:

Which of the following is a type of mechanical comparator?

Optical lever
Zeiss optimeter
Johansson mikrokator
Solex pneumatic gauge

Explanation:

Which one of the following is the most accurate instrument?

Optical projector
Slip gauge
Screw gauge
Vernier caliper

Explanation: