R4RIN – MCQs, Mock Tests | Electrical measurements Electrical Measurement MCQ Question Set 6

In A.C. circuits, power is measured using ____

1. voltmeter
2. ammeter
3. ohmmeter
4. wattmeter

✅ Correct Answer: 4

A wattmeter consists of a current coil and a potential coil.

1. True
2. False
3. all of the above
4. None of the mentioned

✅ Correct Answer: 1

A dynamometer type wattmeter consists of ________

1. only potential coil
2. potential and current coils
3. only current coil
4. no coils

✅ Correct Answer: 2

Controlling torque is provided by gold springs.

1. True
2. False
3. all of the above
4. None of the mentioned

✅ Correct Answer: 2

In a Dynamometer type wattmeter, the fixed coil is split into ________

1. 4
2. 3
3. 2
4. 1

✅ Correct Answer: 3

When a current carrying coil is placed in the magnetic field?

1. no force is exerted
2. voltage is produced
3. power is generated
4. a force is exerted

✅ Correct Answer: 4

Pressure coil of a wattmeter _____

1. has capacitance and inductance
2. has inductance and resistance
3. has resistance and capacitance
4. has only inductance

✅ Correct Answer: 1

Wattmeter reading is not affected by temperature.

1. True
2. False
3. all of the above
4. None of the mentioned

✅ Correct Answer: 2

Dynamometer type wattmeter has ______

1. strong magnetic field
2. intermediate magnetic field
3. weak magnetic field
4. no magnetic field

✅ Correct Answer: 3

Wattmeter reading has errors induced by _____

1. resistance
2. self-capacitance
3. self-inductance
4. mutual inductance

✅ Correct Answer: 4

Current in a pressure coil of the Dynamometer type wattmeter ________

1. lags the applied voltage
2. leads the applied voltage
3. is in phase with the applied voltage
4. there is a phase difference of 90 degrees

✅ Correct Answer: 1

Wattmeters are compensated for errors due to inductance by _________

1. using a series capacitor
2. using a parallel capacitor
3. using a series resistance
4. using a parallel resistance

✅ Correct Answer: 2

Eddy currents are induced in solid metal parts within the thickness of the conductor.

1. True
2. False
3. all of the above
4. None of the mentioned

✅ Correct Answer: 1

What is the effect of frequency on the torque of a moving system?

1. torque is half of the frequency
2. torque is twice the frequency
3. torque is thrice the frequency
4. torque is four times the frequency

✅ Correct Answer: 2

In an ordinary dynamometer, the deflecting torque is ____

1. small
2. medium
3. large
4. very large

✅ Correct Answer: 1

Errors are introduced by _____

1. capacitance
2. inductance
3. resistance
4. impedance

✅ Correct Answer: 2

Power coil has a low value of ________

1. inductance
2. capacitance
3. resistance
4. impedance

✅ Correct Answer: 3

Resistance of pressure coil in a low power factor dynamometer type wattmeter is _____

1. once time
2. three times
3. hundred times
4. ten times

✅ Correct Answer: 4

Low power factor wattmeters are designed to ________

1. have a low torque
2. have a high torque
3. have a medium torque
4. have no torque

✅ Correct Answer: 1

Power loss in the current coil is ______

1. less
2. more
3. intermediate
4. very less

✅ Correct Answer: 2

Pressure coil has no error.

1. True
2. False
3. all of the above
4. None of the mentioned

✅ Correct Answer: 2

Error in a pressure coil can be compensated.

1. True
2. False
3. all of the above
4. None of the mentioned

✅ Correct Answer: 2

Induction type instruments are used for ______

1. A.C. measurements
2. D.C. measurements
3. Resistance measurements
4. Voltage measurements

✅ Correct Answer: 1

Driving system in an induction type single phase energy meter consists of ________

1. one magnet
2. two electromagnets
3. five electromagnets
4. ten magnets

✅ Correct Answer: 2

Series electromagnet consists of _________

1. L shaped laminations
2. T shaped laminations
3. U shaped laminations
4. Y shaped laminations

✅ Correct Answer: 3

Shunt magnet consists of _______

1. N shaped laminations
2. E shaped laminations
3. S shaped laminations
4. M shaped laminations

✅ Correct Answer: 4

Shunt magnet has _____

1. large turns of wire
2. small turns of wire
3. medium turns of wire
4. no turns or wires

✅ Correct Answer: 1

Moving system of the induction type single phase energy meter has _____

1. heavy aluminium disc
2. light aluminium disc
3. medium aluminium disc
4. no aluminium disc

✅ Correct Answer: 2

Braking system consists of _____

1. bar magnet
2. temporary magnet
3. permanent magnet
4. super magnet

✅ Correct Answer: 3

What is the effect of eddy currents in the aluminium disc?

1. varies by a factor of twice the disc length
2. independent of the disc speed
3. varies by a factor of four times the disc size
4. proportional to the disc speed

✅ Correct Answer: 4

An energy meter produces a flux of ∅ when connected to a supply V.

1. True
2. False
3. all of the above
4. None of the mentioned

✅ Correct Answer: 1

The energy meter always measures the load energy correctly.

1. True
2. False
3. all of the above
4. None of the mentioned

✅ Correct Answer: 2

Obtaining correct reading from the energy meter requires ______

1. low resistance and iron losses
2. high resistance and iron losses
3. high resistance and low iron losses
4. low resistance and high iron losses

✅ Correct Answer: 1

Phase angle can be made 90 degrees using ____

1. lead circuit
2. lag circuit
3. special design
4. transformer

✅ Correct Answer: 3

Shading coil consists of many thick turns.

1. True
2. False
3. all of the above
4. None of the mentioned

✅ Correct Answer: 2

Copper shading bands are _________

1. placed as resistance
2. placed as wire
3. placed outside the central limb
4. placed around central limb

✅ Correct Answer: 4

As copper shading bands move up _____

1. more flux is induced
2. less flux is induced
3. intermediate flux is induced
4. no flux is induced

✅ Correct Answer: 1

Shunt flux is made to lag the applied voltage using ________

1. lead circuit
2. lag adjustment
3. lead-lag circuit
4. transformer

✅ Correct Answer: 2

At overloads, magnetic shunt ________

1. aids the series flux
2. diverts series flux
3. maintains zero flux
4. disables the shunt flux

✅ Correct Answer: 2

Energy meter reads correctly when the _______

1. torque is small
2. torque is large
3. torque is medium
4. torque is zero

✅ Correct Answer: 1

Small torque for energy meter is provided ________

1. by a supply
2. by a shading loop
3. by unshaded loop
4. by a transformer

✅ Correct Answer: 2

Driving torque is small and is adjustable.

1. True
2. False
3. all of the above
4. None of the mentioned

✅ Correct Answer: 1

Friction torque is eliminated by ________

1. using lubricating oil
2. by suspending the components in air
3. by adjusting the position of limb
4. by using steel alloy components

✅ Correct Answer: 3

Frictional errors are dominant in an energy meter.

1. True
2. False
3. all of the above
4. None of the mentioned

✅ Correct Answer: 1

At full load, disc ______

1. partially revolves and then stops
2. continuously revolves
3. does not revolve at all
4. revolves in an alternating fashion

✅ Correct Answer: 2

Self braking torque is _____

1. proportional to cube of load current
2. proportional to load current
3. proportional to square of load current
4. proportional to reciprocal of load current

✅ Correct Answer: 3

Self braking action is minimised by _______

1. maintaining high speed for disc
2. maintaining medium speed for disc
3. keeping the disc at rest
4. maintaining low speed for disc

✅ Correct Answer: 4

Overload compensating devices is ______

1. in the form of a magnetic shunt
2. in the form of a series magnet
3. in the form of a transformer
4. in the form of a supply

✅ Correct Answer: 1

Magnitude of flux in an energy meter varies _______

1. due to abnormal currents and voltages
2. due to high resistance and inductance values
3. due to changes in the transformer turns
4. due to the induced e.m.f in the windings

✅ Correct Answer: 1

Phase angles in an energy meter cannot be incorrect.

1. True
2. False
3. all of the above
4. None of the mentioned

✅ Correct Answer: 2