Measurement MCQs Part-8

Measurement MCQs

1. A D'Arsonval movement is_______.

a. Moving iron type

b. Electrodynamometer

c. PMMC

d. Taut band

 

2. What is the value of multiplier resistance on the 50 V range of a dc voltmeter that uses a 500 μA meter movement with an internal resistance of 1 kΩ?

a. 119 kΩ

b. 99 kΩ

c. 199 kΩ

d. 109 kΩ

 

3. Loading effect in a voltmeter can be avoided by________.

a. Using a low sensitive voltmeter

b. Using an accurate and precise instrument

c. Using a high sensitive voltmeter

d. Using high voltage range

 

4. In a D'Arsonval galvanometer, an iron core is usually used between the permanent magnet pole faces. This is used so that_________.

a. The effect of stray magnetic fields is reduced

b. Flux density in the air gap becomes high, thereby a large deflecting torque is produced

c. Moment of inertia of moving parts becomes smaller

d. None of the above

 

5. The sensitivity of a voltmeter is defined as________.

a. Ω/I

b. I/Ω

c. V/Ω

d. Ω/V

 

6. A diode used as rectifier in ac voltmeter should have_______.

a. Low forward current and low reverse current

b. Low forward current and high reverse current

c. High forward current and high reverse current

d. High forward current and low reverse current

 

7. The ac voltmeter using PMMC measures__________.

a. Instantaneous voltage

b. Average voltage

c. Peak voltage

d. True RMS voltage

 

8. The ohm per volt rating on ac ranges as compared to the same rating on dc ranges is__________.

a. Equal

b. More

c. Less

d. None of the above

 

9. Assertion: In case of moving iron instruments, accurate reading of current is not possible at the lower end.

Reason : The scale of moving iron instruments is cramped at the lower end.

a. 'A' is false, but 'R' is true

b. 'A' is true, but 'R' is false

c. Both 'A' and 'R' are, but 'R' is not a correct explanation of A

d. Both 'A' and 'R' are true, and 'R' is a correct explanation of A

 

10. Swamping resistance is connected_______.

a. In series with meter and have high resistance temperature coefficient in order to reduce errors in ammeter

b. In series with the meter and have a negligible resistance coefficient in order to reduce temperature errors in shunted ammeters

c. In series with the shunt to reduce temperature error in shunted ammeters

d. In series with the ammeters to reduce errors on account of friction

 

11. Horizontally mounted moving iron instruments use_______.

a. Eddy  current damping

b. Fluid friction damping

c. Electromagnetic damping

d. Air friction damping

 

12. A static movement in an electrodynamometer type of instrument  is used for________.

a. Eliminating error on the account of low torque to weight ratio

b. Increasing the operating torque of the instruments

c. Eliminating errors on account of external magnetic fields

d. Providing eddy current damping

 

13. The thermocouple type of instruments can be used to measure__________.

a. Both a.c and d.c values of voltage and current

b. Both a.c and d.c values of current only

c. a.c current only

d. d.c. current only

 

14. Which of the following is not an electrothermic type of instrument?

a. Hot wire instruments

b. Thermocouple instruments

c. PMMC instruments

d. Bolometer

 

15. Error due to hysteresis is predominant in__________.

a. Hot-wire instruments

b. Moving iron instruments

c. Electrodynamometer type instruments

d. Moving coil instruments