Electrical And Electronic Measurement MCQs

Question 1

A compensated wattmeter has its reading corrected for error due to

Accepted Answer

power consumed in potential coil

Answer

frequency

Answer

friction

Answer

power consumed in current coil

Question 2

While measuring power in a three phase load by two wattmeter met hod;, the reading of the two wattmeter will be equal and opposite when

Accepted Answer

load is purely inductive

Answer

power factor is unity

Answer

load is balanced

Answer

phase angle is between 60? and 90?

Question 3

A polarized electrolytic capacitor can be used

Accepted Answer

in dc and sinusoidal ac circuits

Answer

only in sinusoidal circuits

Answer

only in dc circuit

Answer

in circuit having any arbitrary waveform of current

Question 4

The major cause of creeping in an energy meter is

Accepted Answer

excessive voltage across the potential coil

Answer

over-compensation for friction

Answer

mechanical vibrations

Answer

stray magnetic field

Question 5

The Lissajous pattern obtained on a CRO screen is shown in the given figure. The frequency ratio of the vertical signal to the horizontal signal is

Accepted Answer

24 V to 36 V

Answer

20 V to 40 V

Answer

29.4 V to 30.6 V

Answer

29.94 to 30.06 V

Question 6

Which one of the following statement is not currect?

Accepted Answer

It is not possible to have precise measurement which are not accurate

Answer

Correctness in measurement requires both accuracy and precision

Answer

Reproducibility and consistency are expressions that best describe precision in measurements

Answer

An instrument with 2% accuracy is better than another with 5% accuracy

Question 7

A slide wire potentiometer has 10 wires at 1 m each. With the help of a standard voltage source of 1.018 V it is standardised by keeping the jockey at 101.8 cm. If the resistance of the potentiometer wires is 1000 ohm, then the value of the working current will be

Accepted Answer

1 mA

Answer

0.1mA

Answer

0.5 mA

Answer

10 mA

Question 8

Natural frequency of vibration at a read used in a vibrating read frequency meter can be increased by

Accepted Answer

decreasing the gap between the read and the electromagnet

Answer

increasing the gap between the read and the electromagnet

Answer

increasing the length of the read

Answer

decreasing the length of the read

Question 9

A single-Phase energymeter is operating on 230 V, 50Hz supply with a load of 20 A for two hours at upf. The meter makes 1380 revolutions in that period. The meter constant is

Accepted Answer

150 rev/kWh

Answer

695 rev/kWh

Answer

0.15 rev/kWh

Answer

11150 rev/kWh