Q.1

Which of the following instruments has non-linear scale?

  1. Moving coil instrument
  2. Moving iron instrument
  3. Electrostatic instrument
  4. Rectifier instrument
Select the answer as per following codes
  • 2 only
  • 2 and 3 only
  • 2, 3 and 1
  • 1, 2, 3 and 4
Q.2

Magnetic field intensity has the dimensions

  • IL
  • I2L
  • IL-1
  • IL-2
Q.3

In a digital measuring device the input electrical signal is in the frequency range of dc to ac (Hz. It must be sampled at a rate of

  • f times/sec
  • 0.5 f times/sec
  • 0.25 f times/sec
  • 2 f times/sec
Q.4

In the wheatstone bridge in figure, each resistance is increased by 0.05%. The value of v0 will be

  • 50 mV
  • 5 mV
  • 0.1 mV
  • zero
Q.5

In the wheatstone bridge in figure, each resistance is increased by 0.05%. The value of v0 will be

  • 50 mV
  • 5 mV
  • 0.1 mV
  • zero
Q.6

Consider the following features of an instrument

  1. suitable for both ac and dc
  2. free from hysteresis and eddy current errors
  3. No waveform and frequency errors
  4. it is essentially a voltmeter
This instrument is
  • moving iron
  • moving coil
  • electrostatic
  • dynamometer
Q.7

Assertion (A): Thermocouple instruments can be used for ac only.

Reason (R): Thermocouple instrument has a non linear scale.

  • Both A and R are true and R is correct explanation of A
  • Both A and R are true but R is not correct explanation of A
  • A is true R is false
  • A is false R is true
Q.8

Which one of the following effects is used in measuring power?

  • Seeback
  • Ferrari
  • Induction
  • Hall
Q.9

The effect of lead resistance is important in measurement of

  • resistance of shunt
  • resistance of shunt winding
  • resistance of ammeter
  • both (a) and (c)
Q.10

A meter has a resistance of 1 Ω and full scale deflection current of 1 mA. To convert into an ammeter of 1 A range, the shunt resistance should be

  • 1000 Ω
  • 1 Ω
  • 0.01 Ω
  • 0.001 Ω
Q.11

The current passing through a resistance of± 0.Ω is 2 ± 0.A. The limiting error in computation of power will be

  • ± 0.7%
  • ± 0.9%
  • ± 1.2%
  • ± 0.3%
Q.12

If A =± 4 and B =±the percentage range of doubt in A - B is

  • 4%
  • 8%
  • 16%
  • 32%
Q.13

Hay's bridge is suitable for inductances having low L/R ratio.

  • True
  • False
Q.14

The most commonly used moving iron instruments are

  • repulsion type
  • attraction type
  • a combination of attraction and repulsion type
  • none of the above
Q.15

A high resistance was measured by loss of charge method. The voltmeter resistance was 1010 ohms. The calculation gave the value of unknown resistance as 0.8 x 109 ohms. The true value of resistance is

  • 0.8 x 109 Ω
  • less than 0.8 x 109 Ω
  • more than 0.8 x 109 Ω
  • either (b) or (c)
Q.16

Two wattmeter method is suitable only for balanced loads.

  • True
  • False
Q.17

A rectifier voltmeter using bridge rectifier and PMMC meter is calibrated to read rms value of sine wave. A triangular wave is applied to it and it reads 6.V. The rms value of triangular wave is

  • about 6.82 V
  • about 7.1 V
  • about 6.5 V
  • about 10 V
Q.18

If the secondary burden of a CTVA and secondary current is 5 A, the load impedance of CT is

  • 0.6 Ω
  • 5 Ω
  • 6 Ω
  • 10 Ω
Q.19

Consider the following instruments

  1. Tangent galvanometer
  2. Rayleigh current balance
  3. Household energy meter
  4. Hot wire ammeter
Out of above absolute instruments are
  • 1, 2 and 3
  • 1, 2 and 4
  • 1 and 2
  • 2, 3 and 4
Q.20

Two resistance R1 and R2 are connected in series R1 =± 5 Ω and R2 =± 3Ω. The total resistance will be

  • 853 ± 2 Ω
  • 853 ± 5 Ω
  • 853 ± 3 Ω
  • 853 ± 8 Ω
Q.21

The function of shunt in an ammeter is to

  • by pass the current
  • increase sensitivity of meter
  • increase resistance of meter
  • all of the above
Q.22

An amplifier has to amplify pulses of 1 H-s duration. The minimum bandwidth of amplifier must be

  • 10 kHz
  • 10 MHz
  • 1 kHz
  • 1 MHz
Q.23

As per BIS, the number of accuracy classes of instrument is

  • 5
  • 6
  • 7
  • 8
Q.24

A sinusoidal signal is measured by CRO. The scale is set at 4 mV/cm. If vertical distance between positive and negative peaks is 6 cm, the peak value of ac signal is

  • 6 mV
  • 12 mV
  • 24 mV
  • 3 mV
Q.25

Moving iron instrument can be used for ac only.

  • True
  • False
Q.26

In electronic voltmeters the measuring device is a

  • moving coil instrument
  • moving iron instrument
  • dynamometer instrument
  • none of the above
Q.27

The resistance in the circuit of the moving coil of a dynamometer wattmeter should be

  • very low
  • low
  • high
  • almost zero
Q.28

A moving iron instrument can be used for

  • dc only
  • ac only
  • both dc and ac
  • dc and high frequency ac
Q.29

Two voltmeters are each 0-V range. Their internal resistances arekΩ andkΩ They are connected is series and a voltage ofV is applied. Their readings respectively will be

  • 266.6 and 133.3 V
  • 133.3 and 266.6 V
  • 200 V each
  • 100 and 300 V
Q.30

A resistance wire strain gauge has gauge factorIf stress ismega newton/m2 and Young's modulus isgiga newton/ m2, the percentage change in gauge resistance due to stress is

  • 0.1
  • 0.2
  • 0.4
  • 0.5
Q.31

A radiation thermometer is suitable for temperatures

  • below 500°C
  • below 100°C
  • above 500°C
  • above 1400°C
Q.32

A 0-voltmeter has a guaranteed accuracy ofof full scale reading. If actual reading isV, the percentage error is

  • 0.83%
  • 1%
  • 1.81%
  • none of the above
Q.33

In a CRO, the frequency of output of time base generator

  • is only one constant value
  • is adjustable
  • varies automatically
  • either (a) or (c)
Q.34

Which of the following does not use the principle of change in inductance?

  • LVDT
  • Inductance displacement transducer
  • Strain gauge
  • Reluctance pick up
Q.35

A moving coil meter has a resistance ofohms and a full scale deflection current ofmA. To convert it into a voltmeter of 0-V range, the series resistance should be

  • 5000 Ω
  • 5050 Ω
  • 4950 Ω
  • 505 Ω
Q.36

In measuring a resistance by voltmeter-ammeter method, the voltmeter can be connected either across supply or across the resistance. If the resistance is low, the voltmeters should be connected

  • across the supply
  • across the resistance
  • either in two positions
  • preferably across the supply
Q.37

In most of instruments, the controlling torque is provided by

  • fluid fraction
  • spring
  • eddy current
  • either (a) or (c)
Q.38

Wheatstone bridge is suitable for low resistances.

  • True
  • False
Q.39

An ammeter has a resistance ofohms and a shunt of 0.Ω. The deflection is θ. If the shunt resistance is increased to 0.Ω, the deflection will be.

  • θ
  • 2θ
  • 0.5θ
  • 0.25θ
Q.40

A temperature sensistive transducer is subjected to sudden temperature change. It takesseconds for transducer to reach equilibrium condition (five times time constant). The time taken to reach half of temperature difference will be

  • 1.38 s
  • 5 s
  • 8.62 s
  • 0.9 s
Q.41

AV voltmeter has an accuracy of ±of full scale deflection. When the reading isV, the actual voltage

  • lies between 217.56 and 226.44 V
  • lies between 217.4 and 226.6 V
  • lies between 216 and 228 V
  • is exact 222 V
Q.42

It is necessary to measure the amplitudes of two signals and also the phase difference between them. This can be done by using a

  • phase meter
  • waveform meter
  • vector voltmeter
  • digital voltmeter
Q.43

Which of the following methods can be used to measure power in a single phase circuit without using wattmeter?

  1. One voltmeter, one ammeter
  2. Two voltmeters, two ammeter
  3. Three voltmeters
  4. Three ammeters
  • 1 and 2 only
  • 2 and 4 only
  • 1 and 3 only
  • 3 and 4 only
Q.44

For measurement of surface temperature of solids the elements of RTD is usually in the shape of

  • bar
  • coil
  • flat grid
  • either (a) or (b)
Q.45

A 0-V voltmeter has a sensitivity of 1 kΩ per volt. The resistance of voltmeter is

  • 1 kΩ
  • 200 kΩ
  • 100 kΩ
  • 50 kΩ
Q.46

To avoid creep in an energy meter

  • two shading bands are put on shunt magnet
  • two shading bands are put on series magnet
  • two holes are cut in the disc on opposite sides of spindle
  • the potential coil is made of very thin wire
Q.47

A wire strain gauge has a gauge factor ofresistance ofΩ and length 1 m. If length of wire changes by .m, change in resistance will be

  • 0.25 Ω
  • 0.5 Ω
  • 1.25 Ω
  • 2.5 Ω
Q.48

In a thermocouple two metal junctions between metals M1 and M2 are kept at temperature T1 and T2. The thermocouple emf is produced because

  • M1, M2 are similar and T1, T2 are equal
  • M1, M2 are similar but T1, T2 are unequal
  • M1, M2 are dissimilar but T1, T2 are equal
  • M1, M2 are dissimilar but T1, T2 are unequal
Q.49

DC ampere hour meter is an indicating instrument.

  • True
  • False
Q.50

The accuracy of measurement by ohmmeter is very good.

  • True
  • False
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