300+ TOP Electronic Instruments MCQ Questions and Answers

ELECTRONIC INSTRUMENTS Questions :-

1. An ammeter is connected in …………….. with the circuit element whose current we wish to measure

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

   Answer: 1

2. A galvanometer in series with a high resistance is called ……………

1. An ammeter
2. A voltmeter
3. A wattmeter
4. None of the above

   Answer: 2

3. An ammeter should have ………….. resistance

1. Infinite
2. Very large
3. Very low
4. None of the above

   Answer: 3

4. A voltmeter is connected in a ………….. with the circuit component across which potential difference is to be measured

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

   Answer: 1

5. A voltmeter should have ………. resistance

1. Zero
2. Very high
3. Very low
4. None of the above

   Answer: 2

6. The sensitivity of a multimeter is given in ……………..

1. O
2. Amperes
3. kO/V
4. none of the above

   Answer: 3

7. If the full-scale deflection current of a multimeter is 50 µA, its sensitivity is ……..

1. 10 kO/V
2. 100 kO/V
3. 50 kO/V
4. 20 kO/V

   Answer: 4

8. If a multimeter has a sensitivity of 1000 O per volt and reads 50 V full scale, its internal resistance is ………..

1. 20 kO
2. 50 kO
3. 10 kO
4. None of the above

   Answer: 2

9. A VTVM has ………. input resistance than that of a multimeter

1. More
2. Less
3. Same
4. None of the above

   Answer: 1

10. The input resistance of a VTVM is about ………..

1. 1000 O
2. 10 kO
3. 20 kO
4. 10 MO

   Answer: 4

11. If the negative potential on the control grid of CRT is increased, the intensity of spot ………….

1. Is increased
2. Is decreased
3. Remains the same
4. None of the above

   Answer: 2

12. For display of signal pattern ………… voltage is applied to the horizontal plates of a CRO

1. Sinusoidal
2. Rectangular
3. Sawtooth
4. None of the above

   Answer: 3

13. Two multimeters A and B have sensitivities of 10 kO/V and 30 kO/V respectively. Then …………..

1. Multimeter A is more sensitive
2. Multimeter B is more sensitive
3. Both are equally sensitive
4. None of the above

   Answer: 2

14. A galvanometer of resistance G is shunted by a very small resistance S. The resistance of the resulting ammeter is ………………

1. GS/(G+S)
2. G+S
3. G-S
4. None of the above

   Answer: 1

15. A VTVM is never used to measure …………..

1. Voltage
2. Current
3. Resistance
4. None of the above

   Answer: 2

16. The sensitivity of a voltmeter which uses a 100 µA meter movement is ……………..

1. 1 kO/V
2. 10 kO/V
3. 5 kO/V
4. Data insufficient

   Answer: 2

17. What is the total resistance of a voltmeter on the 10 V range when the meter movement is rated for 50 µA of full-scale current?

1. 10 kO
2. 20 kO
3. 200 kO
4. None of the above

   Answer: 3

18. The materil used to coat inside the face of CRT is …………..

1. Carbon
2. Sulphur
3. Silicon
4. Phosphorous

   Answer: 4

19. When an ammeter is inserted in the circuit, the circuit current will ………..

1. Increase
2. Decrease
3. Remain the same
4. None of the above

   Answer: 2

20. A series ohmmeter circuit uses a 3 V battery and a 1 mA meter movement. What is the half-scale resistance for this movement?

1. 3 kO
2. kO
3. kO
4. 6 kO

   Answer: 1

21. The most accurate device for measuring voltage is ………….

1. Voltmeter
2. Multimeter
3. CRO
4. VTVM

   Answer: 3

22. The horizontal plates of a CRO are supplied with …………. to observe the waveform of signal.

1. Sinusoidal wave
2. Cosine wave
3. Sawtooth wave
4. None of the above

   Answer: 3

23. A CRO is used to measure ………….

1. Voltage
2. Frequency
3. Phase
4. All of above

   Answer: 4

24. If 2% of the main current is to be passed through a galvanometer of resistance G, then resistance of the shunt required is ……….

1. G/50
2. G/49
3. 49 G
4. 50 G

   Answer: 2

25. Which of the following is likely to have the largest resistance?

1. Voltmeter of range 10 V
2. Moving coil galvanometer
3. Ammeter of range 1 A
4. A copper wire of length 1 m and diameter 3 mm

   Answer: 1

26. An ideal ammeter has ………… resistance

1. Low
2. Infinite
3. Zero
4. High

   Answer: 3

27. The resistance of an ideal voltmeter is …………

1. Low
2. Infinite
3. Zero
4. High

   Answer: 2

28. To send 10% of the main current through a moving coil galvanometer of resistance 99 O the shunt required is …………..

1. 11 O
2. 9 O
3. 100 O
4. 9 O

   Answer: 1

29. A voltmeter has a resistance of G ohms and range V volts. The value of resistance required in series to convert it into voltmeter of range nV is ……………

1. nG
2. G/n
3. G/(n-1)
4. (n-1)G

   Answer: 4

30. An ammeter has a resistance of G ohms and range of I amperes. The value of resistance required in parallel to convert it into an ammeter of range nI is ………….

1. nG
2. (n-1)G
3. G/(n-1)
4. G/n

   Answer: 3

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