Olete.in – MCQs, Mock Tests & Government Job Prep | Lab Measurement (TDR, VNA, Picoprobes) Measurement and Instrumentation MCQ Set 1

The spring material used in a spring control device should have the following property.

1. Should be nonmagnetic
2. Most be of low temperature coefficient
3. Should have low specific resistance
4. All of the above

✅ Correct Answer: 4

For handling greater currents induction watt-meters are used in conjunction with

1. Potential transformers
2. Current transformers
3. Power transformers
4. Either of the above

✅ Correct Answer: 2

The chemical effect of current is used in

1. D.C. ammeter hour meter
2. D.C. ammeter
3. D.C. energy meter
4. None of the above

✅ Correct Answer: 1

The multiplier and the meter coil in a voltmeter are in

1. Series
2. Parallel
3. Series-parallel
4. None of the above

✅ Correct Answer: 1

The pressure coil of a wattmeter should be connected on the supply side of the current coil when

1. Load impedance is high
2. Load impedance is low
3. Supply voltage is low
4. None of the above

✅ Correct Answer: 1

When a capacitor was connected to the terminal of ohmmeter, the pointer indicated a low resistance initially and then slowly came to infinity position. This shows that capacitor is

1. Short-circuited
2. All right
3. Faulty
4. None of the above

✅ Correct Answer: 2

Which of the following devices should be used for accurate measurement of low D.C. voltage?

1. Small range moving coil voltmeter
2. D.C. potentiometer
3. Small range thermocouple voltmeter
4. None of the above

✅ Correct Answer: 2

To measure an A. C. voltage by using an A.C. potentiometer, it is desirable that the supply for the potentiometer in taken

1. From a source which is not the same as the unknown voltage
2. From a battery
3. From the same source as the unknown voltage
4. Any of the above

✅ Correct Answer: 3

Wagner earthing device is used to eliminate errors due to

1. Electrostatic coupling
2. Electromagnetic coupling
3. Both (A) and (B)
4. None of the above

✅ Correct Answer: 1

The two pressure coils of a single phase power factor meter have

1. The same dimensions and the same number of turns
2. The same dimension but different number of turns
3. The same number of turns but different dimensions
4. None of the above

✅ Correct Answer: 1

In a Weston synchronoscope, the fixed coils are connected across

1. Bus-bars
2. Incoming alternator
3. A lamp
4. None of the above

✅ Correct Answer: 2

In a Weston frequency meter, the magnetic axes of the two fixed coils are

1. Parallel
2. Perpendicular
3. Inclined at 60°
4. Inclined at 120°

✅ Correct Answer: 2

If an instrument has cramped scale for larger values, then it follows

1. Square law
2. Logarithmic law
3. Uniform law
4. None of the above

✅ Correct Answer: 2

Alternating current is measured by

1. Induction ammeter
2. Permanent magnet type ammeter
3. Electrostatic ammeter
4. Moving iron repulsion type voltmeter

✅ Correct Answer: 1

The power of a n-phase circuit can be measured by using a minimum of

1. (n - 1) wattmeter elements
2. n wattmeter elements
3. (n + 1) wattmeter elements
4. 2n wattmeter elements

✅ Correct Answer: 1

To measure radio frequency, the suitable frequency meter is

1. Weston frequency meter
2. Reed vibrator frequency meter
3. Heterodoxy frequency meter
4. Electrical resonance frequency meter

✅ Correct Answer: 3

Induction type single phase energy meters measure electric energy in

1. kW
2. Wh
3. kWh
4. VAR

✅ Correct Answer: 3

In majority of instruments damping is provided by

1. Fluid friction
2. Spring
3. Eddy currents
4. None of the above

✅ Correct Answer: 3

A moving iron instrument can be used for

1. D.C. only
2. A.C. only
3. Both D.C. and A.C.
4. None of the above

✅ Correct Answer: 3

In a 3-phase power measurement by two wattmeter method, both the watt meters had identical readings. The power factor of the load was

1. Unity
2. 0.8 lagging
3. 0.8 leading
4. Zero

✅ Correct Answer: 1

It is required to measure the true open circuit e.m.f. of a battery. The best device is

1. D.C. voltmeter
2. Ammeter and a known resistance
3. D.C. potentiometer
4. None of the above

✅ Correct Answer: 3

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

1. D.C. voltmeter
2. Ammeter and a known resistance
3. D.C. potentiometer
4. None of these

✅ Correct Answer: 3

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

1. As long as possible
2. As short as possible
3. Neither too small not too large
4. Very thick

✅ Correct Answer: 1

For measurement of mutual inductance we can use

1. Anderson bridge
2. Maxwell's bridge
3. Heaviside bridge
4. Any of the above

✅ Correct Answer: 3

A power factor meter has

1. One current circuit and two pressure circuits
2. One current circuit and one pressure circuit
3. Two current circuits and one pressure circuit
4. None of the above

✅ Correct Answer: 1

In Weston synchronoscope the moving coil is connected across

1. Bus-bars
2. Incoming alternator
3. Fixed coils
4. None of the above

✅ Correct Answer: 2

Operating torques in analogue instruments are

1. Deflecting and control
2. Deflecting and damping
3. Deflecting, control and damping
4. Vibration and balancing

✅ Correct Answer: 3

A sensitive galvanometer produces large deflection for a

1. Small value of current
2. Large value of current
3. Large value of power
4. Large value of voltage

✅ Correct Answer: 1

In an energy meter braking torque is produced to

1. Safe guard it against creep
2. Brake the instrument
3. Bring energy meter to stand still
4. Maintain steady speed and equal to dr

✅ Correct Answer: 4

The principle on which vector voltmeter is based is

1. That it works on the principle of complex variation
2. That it works on the principle of complex variation
3. Same as digital meter
4. That it measures the amplitude of a single at two points and at the same time measures their phase difference

✅ Correct Answer: 4

Commonly used instruments in power system measurement are

1. Induction
2. Moving coil or iron
3. Rectifier
4. Electrostatic

✅ Correct Answer: 1

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

1. One voltmeter and one ammeter
2. One voltmeter, one ammeter and one wattmeter
3. One voltmeter, one ammeter and one energy meter
4. None of the above

✅ Correct Answer: 2

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

1. Exactly 0°
2. Approximately 0°
3. Exactly 90°
4. Approximately 90°

✅ Correct Answer: 3

For measurements on high voltage capacitors, the suitable bridge is

1. Wien bridge
2. Modified De Santy's bridge
3. Schering Bridge
4. Any of the above

✅ Correct Answer: 3

The operating voltage of a Meggar is about (A) 6 V (B) 12 V (C) 40 V (D)

1. 6 V
2. 12 V
3. 40 V
4. 100 V

✅ Correct Answer: 4

An ohmmeter is a

1. Moving iron instrument
2. Moving coil instrument
3. Dynamometer instrument
4. None of the above

✅ Correct Answer: 2

A dynamometer wattmeter can be used for

1. Both D.C. and A.C.
2. D.C. only
3. A.C. only
4. All of the above

✅ Correct Answer: 1

The disc of an instrument using eddy current damping should be of

1. Conducting and magnetic material
2. Non-conducting and magnetic material
3. Conducting and nonmagnetic material
4. None of the above

✅ Correct Answer: 3

The use of ________ instruments is merely confined within laboratories as standardizing instruments.

1. Absolute
2. Indicating
3. Recording
4. Integrating

✅ Correct Answer: 1

An instrument transformer is used to extend the range of

1. Induction instrument
2. Electrostatic instrument
3. Moving coil instrument
4. All of the above

✅ Correct Answer: 1

The gravity controlled instrument has crowded scale because current is proportional to

1. Balancing weight
2. Deflection angle
3. Sine of deflection angle
4. None of these

✅ Correct Answer: 3

Systematic errors are

1. Instrumental errors
2. Environmental errors
3. Observational errors
4. All of the above

✅ Correct Answer: 4

In a dynamometer 3-phase power factor meter, the planes of the two moving coils are at

1. 0°
2. 60°
3. 90°
4. 120°

✅ Correct Answer: 4

A universal RLC bridge uses

1. Maxwell bridge configuration for measurement of inductance and De Santa’s Bridge for measurement of capacitance
2. Maxwell Wien Bridge for measurement of inductance and modified De Santy's bridge for measurement of capacitance
3. Maxwell Wien Bridge for measurement of inductance and Wien Bridge for measurement of capacitance
4. All of the above

✅ Correct Answer: 2

A voltage of about 200 V can be measured

1. Directly by a D.C. potentiometer
2. A D.C. potentiometer in conjunction with a volt ratio box
3. A D.C. potentiometer in conjunction with a known resistance
4. none of the above

✅ Correct Answer: 2

In a 3-phase power measurement by two wattmeter method the reading of one of the wattmeter was zero. The power factor of the load must be

1. Unity
2. 0.5
3. 0.3
4. Zero

✅ Correct Answer: 2

The scale of a rectifier instrument is

1. Linear
2. Nonlinear
3. Either (A) or (B)
4. Neither (A) nor (B)

✅ Correct Answer: 1

The household energy meter is

1. An indicating instrument
2. A recording instrument
3. An integrating instrument
4. None of the above

✅ Correct Answer: 3

Most common form of A.C. meters met with in every day domestic and industrial installations are

1. Mercury motor meters
2. Commutator motor meters
3. induction type single phase energy meters
4. All of the above

✅ Correct Answer: 3

Resistances can be measured with the help of

1. Watt-meters
2. Voltmeters
3. Ammeters
4. Ohmmeters and resistance bridges

✅ Correct Answer: 4