# 300+ TOP MEASUREMENTS & INSTRUMENTATION Questions and Answers pdf

## MEASUREMENTS and INSTRUMENTATION Questions and Answers :-

1. A 10MHz CRO has
A. 5MHz sweep
B. 10MHz vertical oscillator
C. 10MHz horizontal oscillator
D. 10MHz supply frequency

2. Which of the following instruments can be used to measure AC current only?
A. Permanent Magnet Type ammeter
B. Induction type ammeter
C. Moving iron voltmeter
D. Moving iron ammeter

1. D only
2. B only
3. A, B, D
4. B and D only

3. An oscilloscope indicates
A. Peak to peak value of voltage
B. DC value of voltage
C. RMS value
D. Average value

4. In a ballistic galvanometer, the deflecting torque is proportional to
A. the current through coil
B. square of current through coil
C. square-root of current through coil
D. sine of measured

5. The error of an instrument is normally given as a percentage of
A. measured value
B. full-scale value
C. mean value
D. rms value

6. If the instrument is to have a wide range, the instrument should have
A. Linear scale
B. Square-law scale
C. Exponential scale
D. Logarithmic scale

7. The resistance can be measured most accurately by
A. Voltmeter-ammeter method
B. bridge method
C. multimeter
D. Megger

8. The repeat accuracy of an instrument can be judged from its
A. static error
B. linearity error
C. dynamic error
D. standard deviation of error

9. Which of the following meters has a linear scale?
A. Thermocouple meter
B. Moving iron meter
C. Hot wore meter
D. Moving coil meter

10. No eddy current and hysteresis losses occur in
A. Electrostatic instruments
B. PMMC instruments
C. Moving iron instruments
D. Electrodynamo meter instruments

11. Two voltmeters have the same range 0-400V. The internal impedance are 30,000 Ohms and 20,000 Ohms. If they are connected in series and 600V be applied across them, the readings are
A. 360V and 240V
B. 300V each
C. 400V and 200V
D. one of the meters out of the range and other 100V

12. The full-scale deflection current of an ammeter is 1 mA and its internal resistance is 100Ohm. If this meter is to have full deflection at 5A, what is the value of the shunt resistance to be used?
A. 49.99 Ohms
B. 1/49.99 ohms
C. 1 Ohm
D. 2 Ohms

13. The full-scale deflection current of an ammeter is 1 mA and its internal resistance is 100Ohm. This is to have full deflection when 100V is measureD. What is the value of series resistor to be used?
A. 99.99 K ohms
B. 100 K ohms
C. 99.99 ohms
D. 100 ohms

14. Why is a MISC meter not recommended for DC measurement?
A. The meter is calibrated for AC and it’s error for DC would be high
B. The meter does not respond to DC signals
C. The error is high due to hysteresis effect
D. The error is high due to eddy current effect

15. The EMF of Weston standard cell is measured using
A. Moving- iron meter
B. Moving-coil meter
C. Digital Volt meter
D. Potentiometer

16. A mulliammeter can be used as
A. Voltmeter and ammeter
B. Wattmeter
C. Ohmmeter
D. Frequency meter

17. Which instrument has identical calibration for ac as well as dc values?
A. Hot wire type
B. Moving coil type
C. Induction type
D. Moving iron type

18. An instrument to be used for measurement and control should preferably have
B. Linear output and fast response
C. Non-linear output
D. A highly damped response

19. The current coil of a wattmeter is connected to the CT of R-phase. The potential coil is connected across Y and B phases. The wattmeter measures
A. Active power in R phase
B. Active power of Y phase
C. Reactive power of R phase
D. Power proportional to 3 phase power if the load is balanced

20. The problem of Electro-static coupling in a transformer is acute at
A. Low frequencies
B. Power frequencies
C. High frequencies
D. High load on the transformer

21. Which meter is suitable for the measurement of 10mV at 50MHz?
A. Moving iron voltmeter
B. VTVM
C. Moving coil voltmeter
D. CRO

22. It can be stated that
A. CT operates at almost the same flux density as a PT
B. CT operates with a higher flux density than PT
C. CT operates with considerably lower flux density than a PT
D. no generalisation can be made with regard to the flux densities in CT and PT

23. The thermocouple instruments do not have
A. High sensitivity
B. Absence of frequency error
C. Independence of ambient temperature
D. High degree of measuring accuracy

24. Some wire- wound resistors have bifilar winding. This type of winding is used to
A. Increase the thermal stability
B. Reduce the tolerance
C. Reduce the inductance of winding
D. Double the power rating of the resistor

25. Wien bridge is useful for measuring
A. Very high frequency
B. Low frequency
C. Medium frequency
D. High frequency

### MEASUREMENTS and INSTRUMENTATION Questions and Answers pdf ::

26. A megger is usually
A. Moving iron type instrument
B. Electro-static type instrument
C. Hot-wire type instrument
D. Moving coil type instrument

27. A moving iron ammeter may be compensated for frequency errors by
A. a shunt resistance
B. a series inductance
C. shunt capacitance
D. series resistance

28. Ryall crest voltmeter is used for measurement of
A. AC voltage of any form
B. Low frequency voltage
C. High DC voltage
D. High AC voltage

29. Jewels are used in instruments for the purpose of
A. Damping
B. Torque control
C. Suppressing noise
D. Bearing

30. The thermocouple instrument will measure
A. Current
B. Voltage
C. Flux
D. None of the above

31. A CRO can display
A. AC signals
B. DC signals
C. Both AC and DC signals
D. Time invariant signals

32. The internal resistance of an ammeter should be
A. Very small
B. medium
C. High
D. Infinity

33. A galvanometer has
A. air friction damping
B. fluid friction damping
C. Spring coil damping
D. Eddy current damping

34. Electrostatic instruments are normally used for
A. Low current measurements
B. High current measurements
C. Low voltage measurements
D. High voltage measurements

35. In a moving coil instrument, the deflecting torque is proportional to
A. Current
B. Square of the current
C. Squareroot of the current
D. sine of the measurand

36. The absolute measurement of resistance is done by
A. Ohm’s law method
B. Bridge Method
C. Rayleigh method
D. Lorenz method

37. To measure the flux, devices used are based on
A. Voltaic effect
B. Piezo-electric effect
C. Hall effect
D. Photo-voltaic effect

38. The form factor in AC is the ratio of
A. peak value to average value
B. peak value to rms value
C. rms value to average value
D. rms value to peak value

39. PMMC type instruments normally use
A. Air friction damping
B. Fluid friction damping
C. Eddy current damping
D. None of the above

40. In a moving iron meter, the deflecting torque is proportional to
A. Current through the coil
B. Square of the current through the coil
C. Sine of the measurand
D. Squareroot of the measurand

41. In a gravity controlled instrument, the deflection angle is proportional
A. Measurand
B. Square of the measurand
C. sine inverse of measurand
D. sine of the measurand

42. Ampere is one of the
A. Supplementary units
B. Derived units
C. Base units
D. Units used to measure charge

43. Direct method is used to measure
A. Length
B. Temperature
C. Pressure
D. Voltage

44. A rectifier type instrument is connected to 100VDC and is operated in the DC measuring module reads
A. 111V
B. 90V
C. 50V
D. 100V

45. A permanent magnet moving coil ammeter has a coil resistance of 99ohm and Full Scale DeflectionFSD. current of 0.1mA. Shunt resistance is 1 ohm. Current through the meter at 0.5 F.S.D is
A. 0.007mA
B. 0.05mA
C. 0.023mA
D. 0.1mA

46. One single phase wattmeter operating on 230V and 5A for 5 hours makes 1940 revolutions. Meter constant in revolutions is 400. What is the power factor of the land?
A. 1
B. 0.84
C. 0.73
D. 0.65

47. For power measurement of three phase circuit by two wattmeter method, when the value of power factor is less than 0.5 lagging
A. one of the wattmeters will read zero
B. both give the same readings
C. one of the wattmeter connections will have to be reversed
D. pressure coil of the wattmeter will become ineffective.

48. When using ohmmeter, applied voltage is to be disconnected from the circuit because
A. Voltage source will increase resistance
B. Current will decrease resistance
C. the ohmmeter has its own internal battery
D. non of the above

49. Which wave has the least form factor?
A. Square wave
B. Rectangular wave
C. Sine wave
D. Triangular wave

50. With a sweep time 10ms across the screen the approx. horizontal sawtooth frequency will be
A. 50Hz
B. 100Hz
C. 1kHz
D. 500Hz

51. A spring controlled indicating instrument has a deflection of 90deg for maximum current I. The corresponding deflection for a gravity controlled instrument is
A. 90°
B. 120°
C. 30°
D. 0°

52. It is found that 10A current passes through a resistor of 10ohms. The resistor has 5% tolerance . The error in measurement of current can be as high as 5%. What is max error in measurement of power, calculated from measured value of I and the nominal value of resistor?
A. 100 W
B. 150W
C.50W
D. 200W

53. A resistor of 10Kohms with 5% tolerance is connected in parallel with a 5Kohms resistor of 10% tolerance. What is the tolerance limit for the parallel network?
A. 5%
B. 6.67%
C. 10%
D. 8.33%