R4RIN – MCQs, Mock Tests | Electrical measurements Electrical Measurement MCQ Question Set 4

Range of an electrical instrument depends on ______

1. current
2. voltage
3. power
4. resistance

✅ Correct Answer: 1

Moving coil instruments have a current and voltage rating of _______

1. 100 A and 25 V
2. 50 mA and 50 mV
3. 75 nA and 100 μV
4. 25 μA and 75 V

✅ Correct Answer: 2

A shunt is a ______

1. very high resistance
2. medium resistance
3. very low resistance
4. high resistance

✅ Correct Answer: 3

A shunt can be used to measure large currents.

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

✅ Correct Answer: 1

Current terminals have a small current capacity.

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

✅ Correct Answer: 2

Potential terminals have a ______

1. high current capacity
2. low voltage capacity
3. low current capacity
4. high voltage capacity

✅ Correct Answer: 3

In case of AC ammeters, shunts consist of _______

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

✅ Correct Answer: 4

What is the effect of the ammeter range on the shunt resistance?

1. no effect
2. varies by a factor of multiplying factor
3. varies by a factor of the resistance
4. varies by a factor of unity

✅ Correct Answer: 2

A multiplier is ______

1. non-inductive
2. resistive
3. capacitive
4. non-capacitive

✅ Correct Answer: 1

What is the condition for using a multiplier in A.C. voltmeters?

1. by using ac supply
2. by maintaining a uniform impedance
3. by maintaining a uniform frequency
4. by using a galvanometer

✅ Correct Answer: 3

What is the current transformer?

1. transformer used with an A.C. ammeter
2. transformer used with an D.C. ammeter
3. transformer used with an A.C. voltmeter
4. transformer used with an D.C. voltmeter

✅ Correct Answer: 1

What is the potential transformer?

1. transformer used with an D.C. ammeter
2. transformer used with an A.C. voltmeter
3. transformer used with an D.C. ammeter
4. transformer used with an A.C. voltmeter

✅ Correct Answer: 2

C.T. and P.T. are used for ____

1. measuring low current and voltages
2. measuring very low current and voltages
3. measuring high currentsand voltages
4. measuring intermediate currents and voltages

✅ Correct Answer: 3

The primary winding of a C.T. has ____

1. a larger number of turns
2. no turns at all
3. intermediate number of turns
4. a few turns

✅ Correct Answer: 4

The secondary winding of a C.T. has ______

1. a large number of turns
2. a few turns
3. no turns at all
4. intermediate number of turns

✅ Correct Answer: 1

Turns ration for a C.T. is _______

1. n = Np ⁄ Ns
2. n = Ns ⁄ Np
3. n = 1 ⁄ Np
4. n = Ns

✅ Correct Answer: 2

The primary winding of a P.T. has _____

1. intermediate number of turns
2. no turns at all
3. a larger number of turns
4. a few turns

✅ Correct Answer: 3

The secondary winding of a P.T. has _______

1. a large number of turns
2. intermediate number of turns
3. no turns at all
4. a few turns

✅ Correct Answer: 4

Instrument transformers can be easily replaced.

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

✅ Correct Answer: 1

Instrument transformers provide _____

1. electrical isolation from low rated winding
2. electrical isolation from high rated winding
3. electrical isolation from medium rated winding
4. no electrical isolation at all

✅ Correct Answer: 2

Instrument transformers give same readings irrespective of number of other instruments connected.

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

✅ Correct Answer: 1

C.T. and P.T. are standardized at ____

1. 50 A and 220 V
2. 25 mA and 2.2 kV
3. 5 A and 110 V
4. 75 nA and 1.1 MV

✅ Correct Answer: 3

A 5A ammeter can measure a current of upto 1000 A using a ______

1. 5/1000A C.T.
2. 1000A C.T.
3. 5A C.T.
4. 1000/5A C.T.

✅ Correct Answer: 4

A 110V voltmeter can measure a voltage of upto 110kV using a ___

1. 110000/110V P.T.
2. 110000V P.T.
3. 110V P.T.
4. 110/110000V P.T.

✅ Correct Answer: 1

How can the meter circuit be isolated from the power circuit?

1. by grounding
2. through electrical isolation
3. by physical separation
4. through mechanical isolation

✅ Correct Answer: 2

How are instrument transformers different from shunts and multipliers?

1. they are all the same
2. they have transformers
3. readings are independent of component values
4. they can be used for high voltages and currents

✅ Correct Answer: 3

Transformation ratio of an instrument is defined as _______

1. ratio of primary to secondary phasor
2. ratio of secondary to primary phasor
3. reciprocal of the primary phasor
4. reciprocal of the secondary phasor

✅ Correct Answer: 1

Nominal ratio of an instrument transformer is defined as the _______

1. reciprocal of the rated primary value
2. ratio of rated secondary value to primary value
3. reciprocal of the rated secondary value
4. ratio of rated primary value to secondary value

✅ Correct Answer: 4

Ratio correction factor is defined as ____

1. reciprocal of nominal ratio
2. ratio of nominal ratio to transformation ratio
3. ratio of transformation ratio to nominal ratio
4. reciprocal of transformation ratio

✅ Correct Answer: 3

For a C.T. the turns ratio is defined as the ______

1. n = Np ⁄ Ns
2. n = 1 ⁄ Np
3. n = Ns
4. n = Ns ⁄ Np

✅ Correct Answer: 4

For a P.T. the turns ratio is defined as the ______

1. n = Np ⁄ Ns
2. n = 1 ⁄ Np
3. n = Ns
4. n = Ns ⁄ Np

✅ Correct Answer: 1

Errors are introduced in Current Transformers.

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

✅ Correct Answer: 1

Ratio error is defined as ______

1. Ratio error = Kn⁄R
2. Ratio error = Kn – R⁄R
3. Ratio error = Kn – R
4. Ratio error = 1⁄R

✅ Correct Answer: 2

Ratio error is due to ____

1. iron loss
2. C.T.
3. magnetising component
4. supply voltage

✅ Correct Answer: 1

Phase angle error is due to _____

1. C.T.
2. magnetising component
3. iron loss
4. supply voltage

✅ Correct Answer: 2

In power measurements 180° phase shift is required.

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

✅ Correct Answer: 1

Errors in a C.T. can be minimised by _____

1. making use of laminations
2. having low reactance
3. increasing the secondary winding turns
4. decreasing the primary winding turns

✅ Correct Answer: 2

The secondary leakage reactance of a C.T. ______

1. increases its ratio error
2. decreases its ratio error
3. has no effect on its ratio error
4. increases the impedance of the circuit

✅ Correct Answer: 1

Secondary and primary windings consist of ______

1. copper turns
2. 14 S.W.G copper wire and copper strip respectively
3. iron coils wound around
4. laminations

✅ Correct Answer: 2

Coils of a C.T. are separately wound.

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

✅ Correct Answer: 1

The windings of a C.T. are _______

1. tied together
2. shorted
3. wound over one another
4. grounded

✅ Correct Answer: 3

At high voltages, the current transformers are enclosed in a tank.

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

✅ Correct Answer: 1

Turns compensation is used to obtain ____

1. to compensate the turns
2. to equalise the turns on the windings
3. to protect the equipment
4. transformation ratio equal to nominal ratio

✅ Correct Answer: 4

What is the effect of reducing the secondary turns in a C.T. by 1%?

1. transformation ratio reduces by the same value
2. no effect
3. nominal ratio increase by the same value
4. secondary current increases by the same value

✅ Correct Answer: 1

In a 1000/5 A C.T., the number of secondary turns would be ________

1. 200
2. 199 or 198
3. 5
4. 1000

✅ Correct Answer: 2

In the ring type of core, the secondary winding is ________

1. non-uniformly distributed over the core
2. shorted with the primary winding
3. uniformly distributed over the core
4. connected in the form of a ring

✅ Correct Answer: 3

In a shell type of core, the windings are ________

1. in the form of the shell
2. shorted with the primary windings
3. not wound
4. placed on the central limb

✅ Correct Answer: 4

Mumetal has _______

1. low permeability, high loss
2. high permeability, medium loss
3. medium permeability, high loss
4. high permeability, low loss

✅ Correct Answer: 3

Perminder has ______

1. medium saturation point of permeability
2. low saturation point of permeability
3. no saturation point of permeability
4. high saturation point of permeability

✅ Correct Answer: 4

In a C.T., the primary ampere turns is variable.

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

✅ Correct Answer: 2