## Multiple Choice Questions and Answers on Electronic Instruments

**Q1. An ammeter is connected in …………….. with the circuit element whose current we wish to measure**

- Series
- Parallel
- Series or parallel
- None of the above

**Answer : 1**

**Q2. A galvanometer in series with a high resistance is called ……………**

- An ammeter
- A voltmeter
- A wattmeter
- None of the above

**Answer : 2**

**Q3. An ammeter should have ………….. resistance**

- Infinite
- Very large
- Very low
- None of the above

**Answer : 3**

**Q4. A voltmeter is connected in a ………….. with the circuit component across which potential difference is to be measured**

- Parallel
- Series
- Series or parallel
- None of the above

**Answer : 1**

**Q5. A voltmeter should have ………. resistance**

- Zero
- Very high
- Very low
- None of the above

**Answer : 2**

**Q6. The sensitivity of a multimeter is given in ……………..**

- Ω
- Amperes
- kΩ/V
- none of the above

**Answer : 3**

**Q7. If the full-scale deflection current of a multimeter is 50 ****μA, its sensitivity is ……..**

- 10 kΩ/V
- 100 kΩ/V
- 50 kΩ/V
- 20 kΩ/V

**Answer : 4**

**Q8. If a multimeter has a sensitivity of 1000 ****Ω per volt and reads 50 V full scale, its internal resistance is ………..**

- 20 kΩ
- 50 kΩ
- 10 kΩ
- None of the above

**Answer : 2**

**Q9. A VTVM has ………. input resistance than that of a multimeter**

- More
- Less
- Same
- None of the above

**Answer : 1**

**Q10. The input resistance of a VTVM is about ………..**

- 1000 Ω
- 10 kΩ
- 20 kΩ
- 10 MΩ

**Answer : 4**

**Q11. If the negative potential on the control grid of CRT is increased, the intensity of spot ………….**

- Is increased
- Is decreased
- Remains the same
- None of the above

**Answer : 2**

**Q12. For display of signal pattern ………… voltage is applied to the horizontal plates of a CRO**

- Sinusoidal
- Rectangular
- Sawtooth
- None of the above

**Answer : 3**

**Q13. Two multimeters A and B have sensitivities of 10 kΩ/V and 30 kΩ/V respectively. Then …………..**

- Multimeter A is more sensitive
- Multimeter B is more sensitive
- Both are equally sensitive
- None of the above

**Answer : 2**

**Q14. A galvanometer of resistance G is shunted by a very small resistance S. The resistance of the resulting ammeter is ………………**

- GS/(G+S)
- G+S
- G-S
- None of the above

**Answer : 1**

**Q15. A VTVM is never used to measure …………..**

- Voltage
- Current
- Resistance
- None of the above

**Answer : 2**

**Q16. The sensitivity of a voltmeter which uses a 100 μA meter movement is ……………..**

- 1 kΩ/V
- 10 kΩ/V
- 5 kΩ/V
- Data insufficient

**Answer : 2**

**Q17. 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?**

- 10 kΩ
- 20 kΩ
- 200 kΩ
- None of the above

**Answer : 3**

**Q18. The materil used to coat inside the face of CRT is …………..**

- Carbon
- Sulphur
- Silicon
- Phosphorous

**Answer : 4**

**Q19. When an ammeter is inserted in the circuit, the circuit current will ………..**

- Increase
- Decrease
- Remain the same
- None of the above

**Answer : 2**

**Q20. A series ohmmeter circuit uses a 3 V battery and a 1 mA meter movement. What is the half-scale resistance for this movement?**

- 3 kΩ
- kΩ
- kΩ

- 6 kΩ

**Answer : 1**

**Q21. The most accurate device for measuring voltage is ………….**

- Voltmeter
- Multimeter
- CRO
- VTVM

**Answer : 3**

**Q22. The horizontal plates of a CRO are supplied with …………. to observe the waveform of signal.**

- Sinusoidal wave
- Cosine wave
- Sawtooth wave
- None of the above

**Answer : 3**

**Q23. A CRO is used to measure ………….**

- Voltage
- Frequency
- Phase
- All of above

**Answer : 4**

**Q24. If 2% of the main current is to be passed through a galvanometer of resistance G, then resistance of the shunt required is ……….**

- G/50
- G/49
- 49 G
- 50 G

**Answer : 2**

**Q25. Which of the following is likely to have the largest resistance?**

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

**Answer : 1**

**Q26. An ideal ammeter has ………… resistance**

- Low
- Infinite
- Zero
- High

**Answer : 3**

**Q27. The resistance of an ideal voltmeter is …………**

- Low
- Infinite
- Zero
- High

**Answer : 2**

**Q28. To send 10% of the main current through a moving coil galvanometer of resistance 99 Ω the shunt required is …………..**

- 11 Ω
- 9 Ω
- 100 Ω
- 9 Ω

**Answer : 1**

**Q29. 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 ……………**

- nG
- G/n
- G/(n-1)
- (n-1)G

**Answer : 4**

**Q30. 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 ………….**

- nG
- (n-1)G
- G/(n-1)
- G/n

**Answer : 3**