Measurements & Instrumentation Quiz – Set 10

A direct current can be measured

Consider the following galvanometers

1. D'Arsonval
2. Ballistic
3. Vibration

Which of these are permanent magnet moving coil instruments?

Assertion (A): Hall effect is observed in all metals but is very appreciable in semiconductors.
Reason (R): Hall effect transducer is very suitable for measurement of magnetic flux density.

Assertion (A): The trigger circuit of a CRO is excited by the same signal as Y plates.
Reason (R): The time base generator develops a saw tooth voltage.

A data signal having frequency components from dc to 50 Hz is to be sent through pulse code modulation using an 8 digit code. The minimum carrier channel bandwidth is

If E^b is the potential of accelerating anode, the energy of electrons as they emerge from electron gun is proportional to

A moving iron instrument has

The temperature coefficient of resistance for a thermistor is

To measure an unknown ac voltage by an ac potentiometer it is desirable that supply for the potentiometer is taken

A linear displacement digital transducer generally uses

Two wattmeter method for 3 phase power measurement can be used only for

A coil resonates at 1 MHz with a resonating capacitance of 72 pF. At 500 pF, resonance is obtained with a resonating capacitor of 360 pF. The self capacitance of coil is

A peak responding ac voltmeter using a half wave rectifier has been calibrated to read 1 V for 1 V rms sine wave input. If input is 1 V dc the reading will be

For measuring inductance with high Q, we should use

A resistance strain gauge has a resistance of about

Assertion (A): The speed of a shaft can be measured by using a dc tacho generator.
Reason (R): A two phase servometer can also be used as a speed transducer.

The circuit of figure is used to measure the value R_x. Ammeter resistance R_a = 0.1 Ω voltmeter resistance R_v = 5000 Ω. It R_x1 and R_x2, are the measured values of R_x with switch in position 1 and 2, the mean of R_x1, and R_x2, is

A Weston frequency meter is

The 10 MHz in the specification of CRO means that

Rayleigh current balance is an absolute instrument.

An oscilloscope has an input impedance consisting of 1 MΩ and 20 pF is parallel. A high impedance probe connected to input of this oscilloscope has a 10 MΩ series resistance. This 10 MΩ series resistance

Which of the following is used as detector in audio frequency ac bridges?

Assertion (A): The gall tinsley potentiometer is a coordinate potentiometer and has two exactly similar potentiometers.
Reason (R): An ac potentiometer may measure the unknown voltage in polar form or rectangular coordinate form.

The Y plates of a CRO are excited by a voltage 2 sin 100 t and the X plates are not connected. The display would be

DC voltage of the order of a few mV can be accurately of measured by

If the load current is high, the pressure coil of wattmeter should be connected directly across the load.

In measurements using CRO, Lissajous patterns are used to

A dynamometer wattmeter is suitable for both dc and ac.

The method of frequency compensation in moving iron voltmeter is

A volt ratio box should have low resistance.

Assertion (A): A photovoltaic cell is greatly affected by temperature.
Reason (R): Both germanium and silicon can be used for photovoltaic cells.

Wagner earthing device eliminates

The deflection sensitivity of a CRO is generally expressed in

The response of D'Arsonval galvanometer is over damped if

The scale of dynamometer wattmeter is non linear.

The material used in RTD is

Basically a potentiometer is a device for

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

If two time varying signals of equal magnitudes and 90° phase displacement are applied to X and Y plates of CRO, the display will be

Measurement of non-electrical quantity involves the following subsystems

1. Amplifier block
2. Display block
3. Instrumentation block
4. Transducer block

The correct sequence of these blocks is

Crompton potentiometer has

Assertion (A): For best results the system of a D'Arsonval galvanometer should be slightly under damped.
Reason (R): Degree of damping affects the time taken by the instrument to come to final position.

Assertion (A): An RTD uses platinum coil.
Reason (R): Platinum is a very stable material.

Which of the following, is not a piezoelectric material?

Harmonic distortion analyser

The scale of thermocouple instrument is linear.

Which of the following combinations is not used in thermocouple transducer measurement of temperature?

The dynamic characteristics of capacitive transducer are similar to those of

The electrical power to a megger is provided by

The precision of an instrument indicates its ability to reproduce a certain reading with a given