Measurements & Instrumentation Quiz – Set 2

Measuring of unknown voltage with a dc potentiometer loses its advantage of open circuit measurement when

In figure, the position of voltmeter and ammeter are exchanged. It may result in damage to

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

A variable reluctance tachometer has 180 teeth on rotor. The speed of shaft on which it is mounted in 1200 rpm. The frequency of output pulses is

It is required that a strain gauge has gauge factor of 100. The proper strain gauge is

A 0-200 V voltmeter has an accuracy of 0.75% of full scale reading. If voltage measured is 100 V, the error is

Two voltmeters 0-250 V each having resistances of 5 kΩ and 10 kΩ respectively and are connected in series. To ensure that neither of them goes beyond scale the total voltage which can be applied should be less than

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

If eddy current damping is to be used, the disc of instrument should be

An accelerometer has a seismic mass of 0.05 kg and spring constant of 3 x 10⁵ N/m. If maximum displacement of mass is ± 1 mm, the maximum acceleration which can be measured is

A meter has a square law scale. For 2 A current the deflection in 90°. For a deflection of 45°, the current is

Consider the following operation in respect of Wheatstone bridge (Kb, denotes battery key, Kg denotes galvanometer key)

1. open Kb
2. close Kg
3. close Kb
4. open Kg

The correct sequence of operations is

A meter having 0-1000 μA range and 1000 Ω resistance is required to be changed to 0-100 mA meter. The value of shunt resistance is about

With a variable reluctance tachometer having 60 rotor teeth the count reads 3600 counts per minute. The speed in RPM is

Assertion (A): Shunt of an ammeter has a low resistance.
Reason (R): Shunt may be connected in series or in parallel with ammeter.

The power input and output in a device are 3650 W and 3385 W with each reading in doubt by ± 10 W. The percentage uncertainty in losses is

The resistance of a 125 Ω strain gauge changes by 1 ohm for 4000 micro strain. The gauge factor is

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

The scale of moving iron instrument is linear.

In the balanced bridge shown in figure. X should be

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

A sinusoidal ac voltage of amplitude 100 V is applied to a rectifying device which offers 10 Ω resistance in forward direction and infinite resistance in backward direction. A moving coil ammeter is also connected in the circuit. The reading of ammeter will be

An induction wattmeter can be used for

In Schering bridge, the potential of detector above earth potential is about

Magnetic field intensity has the dimensions

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

The volt ratio box is basically a

The dimensions of EMF are

In 3 phase power measurement by two wattmeter method, both wattmeters had equal reading. The power factor of load is

Which instrument is based on induction principle?

When measuring phase angle between two waves using a CRO, the time base generator is connected to

The scale of a dynamometer is linear when used as

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

Assertion (A): Schering bridge is a low voltage bridge.
Reason (R): Schering bridge is very commonly used for measurement of capacitance.

In a digital measuring device the input electrical signal is in the frequency range of dc to ac (50) Hz. It must be sampled at a rate of

Kelvin's double bridge is used to measure low resistances because

Two numbers are 131 ± 5 and 629 ± 3. The sum of the numbers with range of doubt is

Which of these has a magnetic brake?

LVDT is a

A 24 mm long conductor has a resistance of 128 Ω. The change in resistance is 13.3 Ω and change in length is 1.6 mm under tension. The gauge factor is

Assertion (A): Wien bridge can be used for measuring frequency.
Reason (R): A frequency meter for 50 Hz system has a frequency range of 40 to 60 Hz.

The scale of hot wire instrument is linear.

Which of these has poor overload capacity?

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

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

A moving iron voltmeter reads 250 V when connected to 250 V dc. If connected to 250 V 50 Hz, the voltmeter reading is likely to be

Consider the following Statements regarding resistance strain gauge

1. The gauge factor is in the range of 2 to 5.
2. The resistance changes due to change in specific resistance with strain.
3. The resistance increases with increase in temperature.

Of the above statements, which are correct?

A sinusoidal ac voltage of amplitude 100 V is applied to a rectifying device which offers 10 Ω resistance in forward direction and infinite resistance in reverse direction. The reading on hot wire ammeter will be

A meter coil has a resistance of 100 Ω and a full scale deflection current of 10 mA. To convert it into a voltmeter of 0-200 V range, the series resistance should be

A single element strain gauge bridge has two fixed resistances R₁ and R₁ of 120 Ω each and a variable resistance which gives full deflection at 120 Ω for zero strain and 120.6 Ω for straine e. If gauge factor is 2, strain e is