Q.1

The emf of a Weston cell is 1.V.

  • True
  • False
Q.2

The current in a circuit is measured using a: 1 CT If the ammeter reads 0.6 A, the circuit current is

  • 250 A
  • 90 A
  • 156 A
  • 144 A
Q.3

The input impedance of CRO is about

  • zero
  • 10 Ω
  • 100 Ω
  • one mega ohm
Q.4

Assertion (A): Maxwell bridge is for measuring inductance of medium magnitude.

Reason (R): In Maxwell's bridge the unknown inductance is measured by comparing it with a capacitance.

  • 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.5

A moving coil meter hasΩ resistance and requiresmA for full scale deflection. The shunt resistance required to convert it into 0-2 A ammeter is

  • 0.1021 Ω
  • 0.2041 Ω
  • 0.256 Ω
  • 0.4210 Ω
Q.6

Two ammeters A and B are connected in parallel in a circuit carryingA. Their resistances are 0.8 mΩ. Their readings will be.

  • 55.56 and 44.44 A respectively
  • 44.44 A and 55.56 A respectively
  • 60 A and 40 A respectively
  • 40 A and 60 A respectively
Q.7

It is required to study transients during switching process. Which CRO should be preferred?

  • Ordinary CRO
  • Dual beam CRO
  • Dual trace CRO
  • Storage oscilloscope
Q.8

If the current in a capacitor leads the voltage by 80°, the loss angle of capacitor is

  • 80°
  • 10°
  • 100°
  • 170°
Q.9

If an inductance L is connected in one arm of bridge and resistance R1, R2, R3 in other three arms

  • the bridge cannot be balanced
  • the bridge can be balanced
  • the bridge is balanced for some specified value of frequency
  • the bridge is balanced for some specific values of R1, R2, R3
Q.10

PCM employing 4 bit code is used to send data having frequency range from 0 to 2 kHz. The minimum required bandwidth of carrier channel is

  • 2 kHz
  • 4 kHz
  • 8 kHz
  • 16 kHz
Q.11

A sinusoidal ac voltage of amplitudeV is applied to a rectifying device which offersΩ resistance in forward direction and infinite resistance in reverse direction. The reading on hot wire ammeter will be

  • 10 A
  • 5 A
  • 3.185 A
  • 1.414 A
Q.12

The scale of hot wire instrument is linear.

  • True
  • False
Q.13

The D'Arsonval- movement can be converted into audio frequency ac ammeter by adding a

  • thermocouple
  • transducer
  • chopper
  • rectifier
Q.14

Assertion (A): In hot wire instrument the material of hot wire in generally platinum iridium.

Reason (R): A hot wire ammeter is suitable for ac only

  • 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.15

The scale of hot wire ammeter is

  • linear
  • non-linear
  • cramped
  • absolute linear
Q.16

The power factor of a single phase load can be calculated if instruments available are

  • one voltmeter, one ammeter
  • two ammeters
  • two voltmeters
  • one voltmeter, one ammeter and one wattmeter
Q.17

A variable reluctance type tachometer hasteeth on rotor. The counter recordspulse/sec. The rotational speed is

  • 4800 RPM
  • 5400 RPM
  • 6000 RPM
  • 7200 RPM
Q.18

A volt ratio box should have low resistance.

  • True
  • False
Q.19

The deflection of a DArsonval galvanometer is measured through a mirror and scale. The mirror is 1 m away from the light source. The mirror is mounted on, the moving system. If mirror rotates through 0.2 rad the displacement on the scale is

  • 0.2 m
  • 0.4 m
  • 0.1 m
  • 0.05 m
Q.20

Which of the following is not correct in respect of electrostatic instrument?

  • It is essentially a voltmeter
  • It is suitable for only high voltages
  • It has a uniform scale
  • It can be used for both ac and dc
Q.21

The wave applied to X plates, for ohtaining trace of voltage wave, is

  • sawtooth wave
  • sinusoidal wave
  • rectangular wave
  • either (a) or (c)
Q.22

Assertion (A): A semiconductor strain gauge is more accurate than a resistance strain gauge.

Reason (R): The gauge factor of a semiconductor strain gauge is aboutwhere as the gauge factor of a resistance strain gauge is only about

  • 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.23

Current density has the dimensions

  • IL
  • IL-2
  • IL-3
  • I2L-2
Q.24

Which of the following instruments can be used for dc as well ac upto a few MHz?

  1. Moving iron instrument
  2. Thermocouple instrument
  3. Induction instrument
  4. Moving coil instrument
Select the correct answer as per following codes
  • 2 only
  • 2 and 3 only
  • 1, 2 and 3 only
  • 2 and 4 only
Q.25

Assertion (A): Strain measurement using strain gauge invariably requires a dummy strain gauge.

Reason (R): The resistance of strain gauge depends on temperature.

  • 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.26

In household energy meters the flux of series magnet is in phase with current but the flux of shunt magnet lags the voltage by 88°. The reading of energy meters

  • will be correct
  • will have a negative error
  • will have a positive error
  • may have positive or negative error
Q.27

Assertion (A): In loss of charge method, it is preferable to use an electronic voltmeter.

Reason (R): The resistance of electronic voltmeter is very high.

  • 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.28

In an induction wattmeter, the shading bands are made of non conducting material.

  • True
  • False
Q.29

A moving iron voltmeter readsV when connected toV dc. If connected toVHz, the voltmeter reading is likely to be

  • 250 V
  • 252 V
  • 248 V
  • 210 V
Q.30

When a capacitor is connected to the terminals of an ohmmeter, the pointer indicated a low resistance initially and finally come to infinity position. This shows that capacitor is

  • short circuited
  • all right
  • faulty
  • open circuited
Q.31

The resistance of aΩ strain gauge changes by 1 ohm formicro strain. The gauge factor is

  • 1.5
  • 2
  • 2.5
  • 3
Q.32

A moving coil meter has a shunt of 0.Ω resistance. If coil resistance isΩ and a potential difference ofmV is required across it to cause full scale deflection, the current through shunt is

  • 2.5 A
  • 25 A
  • 0.25 A
  • 0.025 A
Q.33

The current through the coil of an electromagnet is doubled. The magnetic field around the coil

  • is halved
  • is doubled
  • becomes four times
  • remains the same
Q.34

In a moving iron voltmeter the coil has a resistance ofΩ and an inductance of 0.3 H. The swamping resistance inΩ. To ensure correct reading with dc as well asHz ac, the value of capacitor to be connected in parallel with swamping resistance should be

  • 0.0125 μF
  • 0.0311 μF
  • 0.0521 μF
  • 0.0622 μF
Q.35

A Hall effect transducer has KH = - 1 x 10-8. If B = 1 Wb/m2, I = 3 A and bismuth slab is 2 mm wide, the Hall voltage is

  • -7.5 x 10-6 V
  • -15 x 10-6
  • -20 x 10-4 V
  • -22.5 x 10-4 V
Q.36

Two ammeters having resistances of 0.5 Ω and 0.Ω and having full scale reading ofA each are connected in parallel. To ensure that neither of them goes beyond scale, the total current should not be more than

  • 50 A
  • 37.5 A
  • 25 A
  • 40 A
Q.37

The response of a thermistor overs the whole of its temperatures range is

  • linear
  • non-linear
  • almost linear
  • either (a) or (c)
Q.38

The resistance of a dc galvanometer isΩ. A current ofmA causes full scale deflection. To convert it into 0-V voltmeter, we have to use a series resistance of

  • 30000 Ω
  • 29980 Ω
  • 6000 Ω
  • 15 Ω
Q.39

If a shunt ofΩ resistance is used with a galvanometer ofΩ resistance, the multiplying power is

  • 6
  • 5
  • 1/5
  • 1/6
Q.40

Assertion (A): A universal RLC bridge has a battery and also a high frequency ac source.

Reason (R): RLC bridge uses a Wienbridge arrangement for measuring capacitance.

  • 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.41

If the secondary winding of CT is opened when primary coil is carrying current

  • transformer will burn immediately
  • there will be weak flux density in core
  • there will be very high induced voltage in secondary
  • there will be high current in secondary
Q.42

A single element strain gauge bridge has two fixed resistances R1 and R1 ofΩ each and a variable resistance which gives full deflection atΩ for zero strain and 120.6 Ω for straine e. If gauge factor isstrain e is

  • 0.0025
  • 0.0035
  • 0.005
  • 0.0075
Q.43

A 1 mA meter is to be converted to 1 A ammeter. The meter resistance isΩ. The value of shunt resistance is

  • 0.001 Ω
  • 0.1001 Ω
  • 100 Ω
  • 1000 Ω
Q.44

Two ammeters A and B both 0-A have internal resistance of 1 Ω and 0.5 Ω respectively. They are connected in parallel. If total current isA, then

  • IA = IB = 7.5 A
  • IA = 5 A, IB = 10 A
  • IA = 10 A, IB = 5 A
  • IA = 9 A, IB = 6 A
Q.45

A polyphase wattmeter basically consists of two wattmeters. The moving system of two wattmeters

  • are common
  • are separate
  • are generally common
  • are generally separate
Q.46

The percentage limiting error in an instrument reading 8.3 V and having guaranteed accuracy ofof the full scale reading and range of 0-V is

  • 1.81%
  • 0.181%
  • 18.1%
  • 0.0018%
Q.47

The use of thermocouple meters for ac measurement leads to a scale which is

  • linear
  • square law
  • logarithmic
  • exponential
Q.48

Which of the following is not correct?

  • Voltmeter should have a very high resistance
  • An ammeter should have a very low resistance
  • A shunt should have a very low resistance
  • An electronic voltmeter draws appreciable current from source
Q.49

The dead zone in a pyrometer is 0.of span. The calibration is 400°C to 1000°C. What temperature change might occur before it is detected.

  • 0.125°C
  • 0.75°C
  • 0.4°C
  • 1°C
Q.50

Assertion (A): A low power factor wattmeter has special constructional features to ensure accurate measurement.

Reason (R): Extension of wattmeter range in dc circuit can be easily done by using current and potential transformer.

  • 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
0 h : 0 m : 1 s