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%

   Answerb

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

   Answerd

3. Which of these has a magnetic brake?
   1. Dynamometer wattmeter
   2. Energy meter
   3. Thermocouple ammeter
   4. Frequency meter

   Answerb

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

   Answerd

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

   Answerc

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

   Answerc

7. Which of these has poor overload capacity?
   1. Dynamometer instrument
   2. all of rhese
   3. Hot wire instrument
   4. PMMC instrument

   Answerc

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

   Answerb

9. Which instrument is based on induction principle?
   1. Dynamometer wattmeter
   2. Energy meter
   3. Induction wattmeter
   4. Induction wattmeter and Energy meter

   Answerd

10. Magnetic field intensity has the dimensions
    1. none of these
    2. IL
    3. IL⁻¹
    4. I²L

    Answerc

11. The volt ratio box is basically a
    1. all of these
    2. current transformer
    3. potential divider
    4. a high resistance voltmeter

    Answerc

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

    Answerc

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

    Answera

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

    Answerd

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

    Answerc

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

    Answerd

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

    Answera

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

    Answerd

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

    Answerc

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

    Answerb

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

    Answerb

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

    Answerc

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

    Answerc

24. The scale of moving iron instrument is linear.
    1. True
    2. False

    Answerb

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

    Answera

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

    Answerb

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

    Answerd

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

    Answerc

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

    Answerb

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°

    Answera

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

    Answerb

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

    Answerb

33. A volt ratio box should have low resistance.
    1. True
    2. False

    Answerb

34. Answera

35. 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

    Answerb

36. 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

    Answerb

37. 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

    Answerd

38. 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

    Answerd

39. 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

    Answerd

40. Answera

41. Assertion
    (A): A semiconductor strain gauge is more accurate than a resistance
    strain gauge.Reason (R): The gauge factor of a semiconductor strain
    gauge 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

    Answerb

42. Current density has the dimensions
    1. IL⁻²
    2. L²I
    3. I⁻²L²
    4. IL

    Answera

43. 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

    Answerd

44. A capacitance transducer can be used to measure
    1. displacement
    2. level of fluids
    3. All of these
    4. thickness of sheet

    Answerc

45. The dynamometer principle can be used for
    1. wattmeter only
    2. ammeter, voltmeter and wattmeter
    3. voltmeter only
    4. ammeter only

    Answerb

46. 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

    Answerd

47. The scale of hot wire ammeter is
    1. linear
    2. non-linear
    3. absolute linear
    4. cramped

    Answerb

48. 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

    Answerd

49. 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

    Answerd

50. Which one of the following effects is used in measuring power?
    1. Induction
    2. Ferrari
    3. Seeback
    4. Hall

    Answera

51. 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

    Answerd

52. 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

    Answera

Copyright (C) 2016 by (ALL EXAM REVIEW ADDA)