Measurements and Instrumentation Part 2 ONLINE MCQ EE And ECE

Measurements and Instrumentation Part 2

Measurements and Instrumentation Part Two

Instructions: Click the answer button to see the correct answer.

1. The power input and output in a device are 3650 W and 3385 W with each reading in doubt by ± 10 W. The percentage uncertainty in losses is

1. ± 7.55%
2. ± 3.77%
3. ± 15.09%
4. ± 11.32%

Answer: b

Measurements and Instrumentation Part 2

2. A meter coil has a resistance of 100 Ω and a full scale deflection current of 10 mA. To convert it into a voltmeter of 0-200 V range, the series resistance should be

1. 1.9 kΩ
2. 20.1 kΩ
3. 20 kΩ
4. 19.9 kΩ

Answer: d

3. Which of these has a magnetic brake?

1. Dynamometer wattmeter
2. Energy meter
3. Thermocouple ammeter
4. Frequency meter

Answer: b

4. Two numbers are 131 ± 5 and 629 ± 3. The sum of the numbers with range of doubt is

1. 760 + 8
2. 760 ± 2
3. 760 – 8
4. 760 ± 8

Answer: d

Measurements and Instrumentation Part 2

5. Assertion (A): Schering bridge is a low voltage bridge. Reason (R): Schering bridge is very commonly used for measurement of capacitance.

1. Both A and R are true and R is correct explanation of A
2. A is true R is false
3. A is false R is true
4. Both A and R are true but R is not correct explanation of A

Answer: c

6. Assertion (A): Wien bridge can be used for measuring frequency. Reason (R): A frequency meter for 50 Hz system has a frequency range of 40 to 60 Hz.

1. Both A and R are true but R is not correct explanation of A
2. A is false R is true
3. A is true R is false
4. Both A and R are true and R is correct explanation of A

Answer: c

7. Which of these has poor overload capacity?

1. Dynamometer instrument
2. all of rhese
3. Hot wire instrument
4. PMMC instrument

Answer: c

Measurements and Instrumentation Part 2

8. In 3 phase power measurement by two wattmeter method, both wattmeters had equal reading. The power factor of load is

1. 0.5 lagging
2. 1
3. 0.5 leading
4. 0

Answer: b

9. Which instrument is based on induction principle?

1. Dynamometer wattmeter
2. Energy meter
3. Induction wattmeter
4. Induction wattmeter and Energy meter

Answer: d

10. Magnetic field intensity has the dimensions

1. none of these
2. IL
3. IL⁻¹
4. I²L

Answer: c

Measurements and Instrumentation Part 2

11. The volt ratio box is basically a

1. all of these
2. current transformer
3. potential divider
4. a high resistance voltmeter

Answer: c

12. A sinusoidal ac voltage of amplitude 100 V is applied to a rectifying device which offers 10 Ω resistance in forward direction and infinite resistance in backward direction. A moving coil ammeter is also connected in the circuit. The reading of ammeter will be

1. 10 A
2. 14.14 A
3. 3.185 A
4. 5 A

Answer; c

13. A variable reluctance tachometer has 180 teeth on rotor. The speed of shaft on which it is mounted in 1200 rpm. The frequency of output pulses is

1. 3600 per second
2. 5600 per second
3. 1800 per second
4. 4800 per second

Answer; a

Measurements and Instrumentation Part 2

14. Consider the following operation in respect of Wheatstone bridge (Kb, denotes battery key, Kg denotes galvanometer key)1.open Kb 2.close Kg3. close Kb 4.open Kg The correct sequence of operations is

1. 1, 2, 3, 4
2. 3, 1, 2, 4
3. 4, 3, 2, 1
4. 3, 2, 4, 1

Answer: d

15. Two voltmeters 0-250 V each having resistances of 5 kΩ and 10 kΩ respectively and are connected in series. To ensure that neither of them goes beyond scale the total voltage which can be applied should be less than

1. 400 V
2. 500 V
3. 375 V
4. 250 V

Answer: c

16. A 24 mm long conductor has a resistance of 128 Ω. The change in resistance is 13.3 Ω and change in length is 1.6 mm under tension. The gauge factor is

1. 1.2
2. 2.1
3. 2.6
4. 1.6

Answer: d

17. Measuring of unknown voltage with a dc potentiometer loses its advantage of open circuit measurement when

1. range reduction by factor of 10 is employed
2. voltage is larger than range of potentiometer
3. standardisation is done to compensate for drift
4. primary circuit battery is changed

Answer: a

Measurements and Instrumentation Part 2

18. In a digital measuring device the input electrical signal is in the frequency range of dc to ac (50) Hz. It must be sampled at a rate of

1. f times/sec
2. 0.5 f times/sec
3. 0.25 f times/sec
4. 2 f times/sec

Answer: d

19. A meter has a square law scale. For 2 A current the deflection in 90°. For a deflection of 45°, the current is

1. 1 A
2. 1.5 A
3. 1.414 A
4. 1.61 A

Answer: c

20. Consider the following Statements regarding resistance strain gauge 1.The gauge factor is in the range of 2 to 5, 2.The resistance changes due to change in specific resistance with strain, 3.The resistance increases with increase in temperature. Of the above statements, which are correct?

1. 1 and 2
2. 1 and 3
3. 2 and 3
4. 1, 2, 3

Answer: b

Measurements and Instrumentation Part 2

21. A sinusoidal ac voltage of amplitude 100 V is applied to a rectifying device which offers 10 Ω resistance in forward direction and infinite resistance in reverse direction. The reading on hot wire ammeter will be

1. 3.185 A
2. 5 A
3. 10 A
4. 1.414 A

Answer: b

22. When a capacitor is connected to the terminals of an ohmmeter, the pointer indicated a low resistance initially and finally come to infinity position. This shows that capacitor is

1. faulty
2. open circuited
3. all right
4. short circuited

Answer: c

23. If eddy current damping is to be used, the disc of instrument should be

1. conducting and magnetic
2. non-conducting and non-magnetic
3. conducting and non-magnetic
4. non-conducting and magnetic

Answer: c

24. The scale of moving iron instrument is linear.

1. True
2. False

Answer: b

Measurements and Instrumentation Part 2

25. With a variable reluctance tachometer having 60 rotor teeth the count reads 3600 counts per minute. The speed in RPM is

1. 60
2. 3600
3. 36
4. 360

Answer: a

26. When measuring phase angle between two waves using a CRO, the time base generator is connected to

1. Y plate
2. neither X nor Y plates
3. both X and Y plate
4. X plate

Answer: b

27. It is required that a strain gauge has gauge factor of 100. The proper strain gauge is

1. alloy strain gauge
2. constantan strain gauge
3. nichrome strain gauge
4. semiconductor strain gauge

Answer: d

28. A meter having 0-1000 μA range and 1000 Ω resistance is required to be changed to 0-100 mA meter. The value of shunt resistance is about

1. 100 Ω
2. 99 Ω
3. 10 Ω
4. 1 Ω

Answer: c

Measurements and Instrumentation Part 2

29. An induction wattmeter can be used for

1. dc only
2. 50 Hz ac only
3. high frequency ac only
4. both ac and dc

Answer: b

30. If the current in a capacitor leads the voltage by 80°, the loss angle of capacitor is

1. 10°
2. 80°
3. 170°
4. 100°

Answer: a

31. In an induction wattmeter, the shading bands are made of non conducting material.

1. True
2. False

Answer: b

32. The current in a circuit is measured using a 150 : 1 CT If the ammeter reads 0.6 A, the circuit current is

1. 250 A
2. 90 A
3. 156 A
4. 144 A

Answer: b

Measurements and Instrumentation Part 2

33. A volt ratio box should have low resistance.

1. True
2. False

Answer: b

34. A Hall effect transducer has KH = – 1 x 10⁻⁸. If B = 1 Wb/m², I = 3 A and bismuth slab is 2 mm wide, the Hall voltage is

1. -22.5 x 10⁻⁴ V
2. -15 x 10⁻⁶ V
3. -20 x 10⁻⁴
4. -7.5 x 10⁻⁶ V

Answer: b

35. Two ammeters A and B both 0-10 A have internal resistance of 1 Ω and 0.5 Ω respectively. They are connected in parallel. If total current is 15 A, then

1. IA = 10 A, IB = 5 A
2. IA = 5 A, IB = 10 A
3. IA = 9 A, IB = 6 A
4. IA = IB = 7.5 A

Answer: b

Measurements and Instrumentation Part 2

36. Which of the following is not correct?

1. An ammeter should have a very low resistance
2. Voltmeter should have a very high resistance
3. A shunt should have a very low resistance
4. An electronic voltmeter draws appreciable current from source

Answer: d

37. The loss of charge method can be used to measure

1. resistance of shunt
2. resistance of shunt winding
3. all of these
4. insulation resistance of cable

Answer: d

38. Assertion (A): Maxwell bridge is for measuring inductance of medium magnitude. Reason (R): In Maxwell’s bridge the unknown inductance is measured by comparing it with a capacitance.

1. Both A and R are true and R is correct explanation of A
2. A is false R is true
3. Both A and R are true but R is not correct explanation of A
4. A is true R is false

Answer: d

39. Assertion (A): A semiconductor strain gauge is more accurate than a resistance strain gauge. Reason (R): The gauge factor of a semiconductor straingauge is about 100 where as the gauge factor of a resistance strain gauge is only about 2.

1. A is false R is true
2. Both A and R are true and R is correct explanation of A
3. Both A and R are true but R is not correct explanation of A
4. A is true R is false

Answer: b

40. Current density has the dimensions

1. IL⁻²
2. L²I
3. I⁻²L²
4. IL

Answer: a

Measurements and Instrumentation Part 2

41. The resistance of a dc galvanometer is 20 Ω. A current of 10 mA causes full scale deflection. To convert it into 0-300 V voltmeter, we have to use a series resistance of

1. 6000 Ω
2. 30000 Ω
3. 15 Ω
4. 29980 Ω

Answer: d

42. A capacitance transducer can be used to measure

1. displacement
2. level of fluids
3. All of these
4. thickness of sheet

Answer: c

43. The dynamometer principle can be used for

1. wattmeter only
2. ammeter, voltmeter and wattmeter
3. voltmeter only
4. ammeter only

Answer: b

Measurements and Instrumentation Part 2

44. Assertion (A): In hot wire instrument the material of hot wire in generally platinum iridium. Reason (R): A hot wire ammeter is suitable for ac only

1. A is false R is true
2. Both A and R are true and R is correct explanation of A
3. Both A and R are true but R is not correct explanation of A
4. A is true R is false

Answer: d

45. The scale of hot wire ammeter is

1. linear
2. non-linear
3. absolute linear
4. cramped

Answer: b

46. A moving coil meter has a shunt of 0.02 Ω resistance. If coil resistance is 1000 Ω and a potential difference of 500 mV is required across it to cause full scale deflection, the current through shunt is

1. 0.025 A
2. 0.25 A
3. 2.5 A
4. 25 A

Answer: d

Measurements and Instrumentation Part 2

47. Consider the following features of an instrument 1.suitable for both ac and dc,2.free from hysteresis and eddy current errors,3.No waveform and frequency errors,4.it is essentially a voltmeter. This instrument is

1. moving coil
2. dynamometer
3. moving iron
4. electrostatic

Answer: d

48. Which one of the following effects is used in measuring power?

1. Induction
2. Ferrari
3. Seeback
4. Hall

Answer; a

49. The effect of lead resistance is important in measurement of

1. resistance of ammeter
2. resistance of shunt winding
3. resistance of shunt
4. resistance of shunt and resistance of ammeter

Answer: d

50. A resistance wire strain gauge has gauge factor 2. If stress is 100 mega newton/m² and Young’s modulus is 200 giga newton/ m², the percentage change in gauge resistance due to stress is

1. 0.1
2. 0.
3. 0.3
4. 0.2

Answer: a

Measurements and Instrumentation Part 2