300+ TOP Measurement & Instruments Objective Questions and Answers pdf

MEASUREMENT and INSTRUMENTS Objective Questions and Answers pdf free Download :-

1. Hysteresis of an instrument means:
a) The change in the same reading when input is first increased and then decreased
b) The reliability of the instrument
c) The repeatability of the insrument
d) The inaccuracy due to change in temperature

ANSWER : A

2. In which part of the scale does the pointer indicate more accurately
a) In the first third of the cycle
b) In the first half of the cycle
c) In about middle of the scale
d) In the last third of the cycle

ANSWER : C

3. For measuring an unknown electrical quantity, select the meter with
a) Highest range and work down
b) Lowest range and work up
c) Middle range and can be work up or down depending
d) Any of the above

ANSWER : A

4. The ratio of maximum displacement deviation to the full scale deviation of the instrument is called:
a) Static sensitivity
b) Accuracy
c) Linearity
d) Precision

ANSWER : C

5. A 150 V moving iron voltmeter of accuracy class 1.0 reads 75 V when used in a circuit under a standard conditions. The maximum possible percentage error in the reading is:
a) 0.5
b) 1.0
c) 2.0
d) 4.0

ANSWER : C

6. The relative error is the:
a) Difference of the measured value and the true value
b) Ratio of absolute error to the measured value of the quantity under measurement
c) Ratio of the absolute error to the true value of the quantity under measurement
d) Ratio of the probable error to the true value of the quantity under measurment

ANSWER : C

7. The moving iron voltmeters are likely:
a) To indicate the same value of the ac as on dc
b) To indicate higher value of ac than on dc
c) To indicate lower value of ac than on dc
d) The moving iron instruments should not be used for dc measurment

ANSWER : C

8. The power measurement in a balanced 3-phase circuit can be done by:
a) One wattmeter method
b) Two wattmeter method
c) Three wattmeter method
d) Any of the above method

ANSWER : D

9. Anderson’s bridge is a modification of:
a) Maxwell’s wien bridge
b) Hay’s bridge
c) Schering bridge
d) Owen bridge

ANSWER : A

10. Ballastic tests are used in magnetic measurements for the determination of:
a) Flux density of the specimen
b) B-H curve of the specimen
c) Hysteresis loop of the specimen
d) All the above

ANSWER : D

11. Anderson Bridge is used to measure:
a) L
b) C
c) V
d) I

ANSWER : A

12. Hay’s Bridge is suitable for the measurement of:
a) Inductances with Q>10
b) Inductances with Q<10
c) Capacitors with high dissipation factor
d) Capacitors with low dissipation factor

ANSWER : A

13. The frequency can be measured by using:
a) Wien’s bridge
b) De Sauty’s bridge
c) Schering’s bridge
d) Anderson’s bidge

ANSWER : C

14. The ballistic galvanometer is usually lightly damped so that:
a) It may oscillate
b) It may remain stable
c) Amplitude of the first swing is large
d) Amplitude of the first swing is small

ANSWER : C

15. B-H Curve is used to determination of:
a) Hysteresis loss
b) Iron loss
c) Eddy current loss
d) Both (a) and (b)

ANSWER : A

16. Magnetic materials can be tested by:
a) Self inductance bridge
b) Cambell’s mutual inductance bridge
c) AC potentiometer
d) All the above

ANSWER : D

17. A PMMC instrument can be used as a fluxmeter by:
a) Using low resistance shunt
b) Removing the control spring
c) Making the control springs of large moment of inertia
d) Using a high series resistance

ANSWER : B

18. Open circuit fault in a cable can be located by:
a) Blavier’s test
b) Capacity test
c) Varley loop test
d) Murray loop test

ANSWER : B

19. In CRO the time base signal is applied to:
a) Y-plates
b) X-plates
c) Either X-plate or Y-plate
d) Both X-plate and Y-plate

ANSWER : B

20.In CRO astigmatism is:
a) Source of generating fast electrons
b) Media for absorbing secondary emission electrons
c) An additional focus control
d) Time-delay control in the vertical deflection system

ANSWER : C

21. The main advantage of crystal oscillator is that its output is:
a) A Constant frequency range
b) DC
c) 50 Hz to 60 Hz
d) Variable frequency

ANSWER : A

22. Which of the following statement is true of phase-shift type and Wien-bridge type R-C oscillators:
a) Both use positive feedback
b) The former uses positive feedback only whereas the latter uses both positive and negative feedback
c) The former uses both positive and negative feedback
d) Both use negative feedback

ANSWER : B

23. Moving iron and PMMC instruments can be distinguished from each other by looking at:
a) Pointer
b) Terminal size
c) Scale
d) Scale range

ANSWER : C

24. In a dynamo-meter type of moving coil instrument a swamping resistance is provided inorder to:
a) Control the deflection torque
b) Reduce the bulk of the moving system
c) Reduce the current flowing through the moving coil
d) Provide equal time constant for moving coil and fixed coil, when used for ac measurement

ANSWER : D

25. The deflection of hot-wire instrument depends on:
a) Instantaneous value of alternating current
b) Average value of current
c) RMS value of the alternating current
d) Voltage

ANSWER : C

26. If two meters X and Y requires 40mA and 50mA respectively, to give full scale deflection, then:
a) X is more sensitive
b) Y is more sensitive
c) Both X and Y are equally sensitive
d) It would not be possible to access the sensitivity on the basis of the given data

ANSWER : A

27. The reliability of the instrument refer to:
a) Measurement of changes due to temperature variations
b) Degree to which repeatability continues to remain within specified limits
c) The life of the instrument
d) The extent to which the characteristics remain linear

ANSWER : B

28. The damping torque must operate only when the moving system of the indicating instrument is:
a) Actually moving
b) Stationary
c) Just starting to move
d) Near its full deflection

ANSWER : A

29. If a voltmeter is connected, like an ammeter in series to the load:
a) The measurement reading will be too high
b) Almost no current will flow in the circuit
c) The meter will burn
d) An instantaneously high current will flow

ANSWER : B

30. Preferred material for permanent magnet is:
a) Stainless steel
b) Alnico
c) Tungsten steel
d) Soft iron

ANSWER : B

31. Air friction damping is used in the instruments which is:
a) Moving iron
b) Moving coil
c) Induction
d) Hot wire

ANSWER : A

32. PMMC instrument gives uniform scale because:
a) It uses spring control
b) It uses eddy current damping
c) The deflection torque is proportional to the instrument current
d) Both (a) and (c)

ANSWER : D

33.An instrument that is capable of measuring only dc is:
a) Moving coil
b) Moving iron
c) Thermo couple
d) None of the above

ANSWER : A

34. Maxwell-Wien bridge is used to measure:
a) Inductance
b) Capacitance
c) Dielectric loss
d) Frequency

ANSWER : A

35.A ballistic galvanometer is used to measure:
a) Charge
b) Current
c) Voltage
d) Frequency

ANSWER : A

36. ____ factor is the ratio of total flux to the useful flux in a magnetic circuit:
a) Form factor
b) Leakage
c) Utility
d) Dispersion

ANSWER : B

37. For eliminating the effect of earth capacitance from the bridge network we use:
a) Wagner’s earthing device
b) High voltage at low frequency
c) Low voltage at high frequency
d) Campbell-maxwell device

ANSWER : A

38. The most commonly used null deflector in a power frequency ac bridge is a:
a) Vibration galvanometer
b) D’Arsanval galvanometer
c) Ballistic galvanometer
d) Tachometer

ANSWER : A

39. For measuring emf of a standard cell we use:
a) Galvanometer
b) Potentiometer
c) Zener reference
d) Electro-dynamic voltmeter

ANSWER : B

40.Loss of charge method is used to measure:
a) Low R
b) High R
c) Low L
d) High L

ANSWER : B

41. Megger is an instrument used for the measurement of:
a) High resistance and insulation resistance
b) Medium resistance
c) Low resistance
d) Leakage current

ANSWER : A

42. Vibration reeds are employed in:
a) Frequency meter
b) Power factor meter
c) Synchroscope
d) Megger

ANSWER : A

43. Kelvin double bridge is best suited for the measurement of:
a) Inductance
b) Capacitance
c) Low resistance
d) High resistance

ANSWER : C

44. Introduction of dielectric:
a) Increases the capacitance
b) Reduces the breakdown voltage
c) Reduces the mechanical voltage
d) Increases the size of the capacitor

ANSWER : A

45. The material used to make standard resistance is:
a) Manganin
b) Aluminium
c) Nichrome
d) Platinum

ANSWER : A

46. Which of the following instruments have least torque/weight ratio:
a) Dynamometer type
b) PMMC
c) Attraction type moving iron
d) Repulsion type moving iron

ANSWER : A

47. The instrument having its deflection depends upon average value is:
a) Moving iron
b) Hot wire
c) Rectifier type
d) Induction type

ANSWER : C

48. Which of the following instruments can be used for full scale deflection of 300o:
a) PMMC
b) Induction type
c) Hot wire
d) Electrostatic

ANSWER : B

49.While testing cables the galvanometer used should be initially short-circuited in order to protect it from sudden initial inrush currents as the cable have:
a) A low value of initial resistance
b) A low value of initial capacitance
c) A high value of initial capacitance
d) Both (a) and (b)

ANSWER : C

50. A Ohmmeter is basically:
a) A ammeter
b) A voltmeter
c) A multimeter
d) None of the above

ANSWER : A