Explore topic-wise MCQs in Testing Subject.

This section includes 657 Mcqs, each offering curated multiple-choice questions to sharpen your Testing Subject knowledge and support exam preparation. Choose a topic below to get started.

1.

In a low power factor wattmeter, the resistance of pressure coil is more than in ordinary wattmeter.

A. True
B. False
Answer» B. False
Discussion
2.

If two time varying signals of equal magnitude and zero phase displacement are applied to X and Y plates respectively; of CRO, the display will be

A. a straight line
B. a circle
C. an ellipse
D. a square
Answer» B. a circle
Discussion
3.

Wagner earthing device is used to eliminate error due to

A. electromagnetic coupling
B. electrostatic coupling
C. both electrostatic and electromagnetic coupling
D. either (a) or (b)
Answer» C. both electrostatic and electromagnetic coupling
Discussion
4.

The moving iron instruments are generally repulsion type.

A. True
B. False
Answer» B. False
Discussion
5.

Gauge factor of a strain gauge is

A. unit change in resistance per unit change in length
B. change in resistance per unit change in length
C. unit change in length per unit change in resistance
D. none of the above
Answer» B. change in resistance per unit change in length
Discussion
6.

The total insulation resistance consists of insulation volume resistance and surface leakage resistance.

A. True
B. False
Answer» B. False
Discussion
7.

Assertion (A): Capacitance effect can be used to measure thickness of sheets, displacement and pressure.Reason (R): Capacitance between two plates depends on the area of plates, distance between plates and permittivity of medium.

A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true R is false
D. A is false R is true
Answer» B. Both A and R are true but R is not correct explanation of A
Discussion
8.

Assertion (A): Energy meters use induction principle.Reason (R): Induction wattmeter is less accurate than a dynamometer wattmeter.

A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true R is false
D. A is false R is true
Answer» C. A is true R is false
Discussion
9.

In a current transformers

A. the number of turns in primary and secondary windings are nearly equal
B. the number of primary turns is very small as compared to number of secondary turns.
C. the number of secondary turns is very small as compared to the number of primary turns
D. either (a) or (c).
Answer» C. the number of secondary turns is very small as compared to the number of primary turns
Discussion
10.

A dynamometer wattmeter can be used for

A. dc only
B. ac only
C. dc and 50 Hz ac
D. dc and high frequency ac
Answer» D. dc and high frequency ac
Discussion
11.

The time base of a high frequency CRO whose screen diameter is 10 cm is set at 10 sec/cm. The lowest frequency which can be fully displayed on the screen is

A. more than 100 kHz
B. equal to 100 kHz
C. equal to 10 kHz
D. less than 10 kHz
Answer» D. less than 10 kHz
Discussion
12.

RTD is generally suitable for temperature up to

A. about 800 C
B. about 1500 C
C. about 200 C
D. about 50 C
Answer» B. about 1500 C
Discussion
13.

The accuracy of a multimeter is about

A. 0.5%
B. 3%
C. 0.01%
D. 10%
Answer» C. 0.01%
Discussion
14.

Eddy currents are essential for the deflecting torque of an induction wattmeter.

A. True
B. False
Answer» B. False
Discussion
15.

To measure moisture in wood, the most suitable method is

A. electric conduction
B. electrical-capacitive
C. absorption of radiation
D. equilibrium-moisture Vs humidity
Answer» B. electrical-capacitive
Discussion
16.

An E transformer is a

A. displacement transducer
B. velocity transducer
C. acceleration transducer
D. pressure transducer
Answer» B. velocity transducer
Discussion
17.

Load cell uses

A. piezoelectric crystal
B. capacitor
C. mutual inductance
D. strain gauge
Answer» E.
Discussion
18.

Piezoelectric effect can be used to measure

A. force
B. strain
C. acceleration
D. all of the above
Answer» E.
Discussion
19.

A current of 3.18 A is flowing through resistance of 35.68 Ω. The voltage drop across resistance to the appropriate number of significant figures is

A. 113.4624 V
B. 113.462 V
C. 113.46 V
D. 113 V
Answer» E.
Discussion
20.

Assertion (A): A dc potentiometer measures the true open circuit emf of a source.Reason (R): At balance point, a dc potentiometer does not draw any current from the source.

A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true R is false
D. A is false R is true
Answer» B. Both A and R are true but R is not correct explanation of A
Discussion
21.

The resistance of series field winding is a low resistance.

A. True
B. False
Answer» B. False
Discussion
22.

Assertion (A): In two wattmeter method of 3 phase power measurement, one of the wattmeters would read negative if power factor of load is less than 0.5.Reason (R): In two wattmeter method of 3 phase power measurement, both the wattmeters would show equal readings if power factor of load is unity.

A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true R is false
D. A is false R is true
Answer» C. A is true R is false
Discussion
23.

In a megger the moving coil meter has a permanent magnet.

A. True
B. False
Answer» B. False
Discussion
24.

The pointer of an indicating instrument should be

A. very light
B. very heavy
C. neither heavy nor light
D. heavy
Answer» B. very heavy
Discussion
25.

The resistance of resistance strain gauge is about

A. 5 Ω
B. 50 Ω
C. 120 Ω
D. 0.5 Ω
Answer» D. 0.5 Ω
Discussion
26.

The most serious problems in ac bridge measurement is

A. eddy currents
B. leakage current
C. residual magnetism
D. stray fields
Answer» E.
Discussion
27.

Assertion (A): An electrostatic voltmeter is free from hysteresis and eddy current errors.Reason (R): An electrostatic voltmeter has a number of fixed and moving vanes in parallel.

A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true R is false
D. A is false R is true
Answer» C. A is true R is false
Discussion
28.

In order to achieve accuracy, the slide wire of a potentiometer should be

A. as long as possible
B. as short as possible
C. neither too long nor too short
D. very thin
Answer» B. as short as possible
Discussion
29.

In measuring resistance using voltmeter and ammeter, the resistances of voltmeter and ammeter also affect the accuracy of measurement.

A. True
B. False
Answer» B. False
Discussion
30.

In a single phase power factor meter the phase difference between currents in the two pressure coils is

A. exactly 0
B. approximate 0
C. exactly 90
D. approximate 90
Answer» D. approximate 90
Discussion
31.

In an ac coordinate potentiometer, the currents inphase and quadrature potentiometer are adjusted to be

A. out of phase by 90
B. in phase
C. out of phase by 45
D. out of phase 180
Answer» B. in phase
Discussion
32.

Schering bridge operates at a high voltage of about 10 kV.

A. True
B. False
Answer» B. False
Discussion
33.

In a platinum RTD, the change in resistance for a temperature rise of 50 C is about

A. 2%
B. 10%
C. 20%
D. 40%
Answer» D. 40%
Discussion
34.

The switch board instruments

A. should be mounted in vertical position
B. should be mounted in horizontal position
C. should be mounted at about 45
D. should be mounted at about 80
Answer» B. should be mounted in horizontal position
Discussion
35.

Pirani gauge is used to measure

A. very low pressure
B. high pressure
C. pressure in the range of 1 atmosphere
D. fluid flow
Answer» B. high pressure
Discussion
36.

The channel required for FM telemetry is

A. same as required for AM telemetry
B. smaller than that required by AM telemetry
C. 100 times that required for AM telemetry
D. 10 times that required for AM telemetry
Answer» D. 10 times that required for AM telemetry
Discussion
37.

Assertion (A): A 3 phase wattmeter consists of two wattmeters mounted in one case.Reason (R): Power measurement in a 3 phase circuit can be conveniently done by two wattmeter method.

A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true R is false
D. A is false R is true
Answer» B. Both A and R are true but R is not correct explanation of A
Discussion
38.

Assertion (A): Double Kelvin's bridge is used to measure low resistances.Reason (R): In low resistance, the contact and lead resistances are very important.

A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true R is false
D. A is false R is true
Answer» B. Both A and R are true but R is not correct explanation of A
Discussion
39.

Shaft encoder is used to measure

A. angular position
B. linear position
C. linear velocity
D. linear acceleration
Answer» B. linear position
Discussion
40.

Assertion (A): Moving iron instrument can be used on ac or dc.Reason (R): In a moving iron instrument deflecting torque is proportional to square of current.

A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true R is false
D. A is false R is true
Answer» B. Both A and R are true but R is not correct explanation of A
Discussion
41.

Assertion (A): The scale a PMMC ammeter is linear.Reason (R): The deflecting torque of PMMC is proportional to current in the coil.

A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true R is false
D. A is false R is true
Answer» B. Both A and R are true but R is not correct explanation of A
Discussion
42.

Assertion (A): Hay's bridge in particularly suitable for measuring inductance having a comparatively low resistance.Reason (R): In Hay's bridge the value of frequency supply must be known.

A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true R is false
D. A is false R is true
Answer» C. A is true R is false
Discussion
43.

The device having highest photo sensitivity is

A. photoconductive cell
B. photovoltaic cell
C. photodiode
D. phototransistor
Answer» B. photovoltaic cell
Discussion
44.

Use of high permeability core in moving iron instrument helps in

A. reducing size of meter
B. increasing sensitivity
C. reducing temperature error
D. all of the above
Answer» C. reducing temperature error
Discussion
45.

The two pressure coils in a single phase power factor meter of turns

A. the same dimension and the same numbers of turns
B. the same dimension but different number of turns
C. different dimension and different numbers of turns
D. different dimension but the same numbers of turns
Answer» B. the same dimension but different number of turns
Discussion
46.

For use at 50 Hz the range of scale of vibrating reed frequency meter is

A. 25 - 75 Hz
B. 40 - 60 Hz
C. 47 - 53 Hz
D. 42 - 58 Hz
Answer» D. 42 - 58 Hz
Discussion
47.

Consider the following statements about a moving iron instrument It is an unpolarised instrument.It has permanent magnet.It has a fixed coil.It has two iron vanes. Of these statements

A. 1, 2, 3 are correct
B. 1, 2, 4 are correct
C. 1, 3 and 4 are correct
D. 2, 3, 4 are correct
Answer» D. 2, 3, 4 are correct
Discussion
48.

An instrument of accuracy class 1 can have an error equal to

A. + 1% of reading
B. 1% of reading
C. 1% of full scale deflection
D. + 1% of full scale deflection
Answer» D. + 1% of full scale deflection
Discussion
49.

Assertion (A): When frequencies of signals fed to X and Y plates of CRO are multiples of each other, Lissajous pattern is displayed on screen.Reason (R): In a CRO, the vertical deflection is proportional to voltage applied to Y plates.

A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true R is false
D. A is false R is true
Answer» C. A is true R is false
Discussion
50.

In portable instruments, damping is provided by

A. spring
B. gravity
C. eddy current
D. either (a) or (c)
Answer» B. gravity
Discussion