# Electrical and Electronics Measurement & Instrumentation - Set - 6

1)   For a second order instrument if the value of the damping ratio is equal to zero, then the

a. Output will exhibit constant amplitude oscillation
b. Initially output will be oscillatory and gradually it will die down
c. Initially output will be oscillatory and gradually amplitude of oscillation will increase
d. Output does not exhibit any oscillations
 Answer  Explanation  Related Ques ANSWER: Output will exhibit constant amplitude oscillation Explanation: No explanation is available for this question!

2)   Commercial accelerometer, which is a second order instruments are generally designed for the damping ratio of the range of

a. 0.2 – 0.4
b. 0.6 – 0.8
c. 0.707 – 1
d. 1 – 1.5
 Answer  Explanation  Related Ques ANSWER: 0.6 – 0.8 Explanation: No explanation is available for this question!

3)   The process of measurement

a. Always disturbs the system being measured
b. It may or may not disturb the system being measured
c. Never disturbs the system being measured
d. None of these
 Answer  Explanation  Related Ques ANSWER: Always disturbs the system being measured Explanation: No explanation is available for this question!

4)   The difference between the measured value and the true value is known as

a. Relative error
b. Random error
c. Absolute error
d. Systematic error
 Answer  Explanation  Related Ques ANSWER: Absolute error Explanation: No explanation is available for this question!

5)   In the systematic errors, the errors in the output of the measurement system are

a. All the errors will be positive
b. All the errors will be negative
c. Either all the errors will be positive or all the errors will be negative
d. None of the these
 Answer  Explanation  Related Ques ANSWER: Either all the errors will be positive or all the errors will be negative Explanation: No explanation is available for this question!

6)   Systematic errors in a measurement system are caused by

a. System disturbance during measurement
b. Effect of environmental changes
c. Use of uncalibrated instruments
d. All of these
 Answer  Explanation  Related Ques ANSWER: All of these Explanation: No explanation is available for this question!

7)   In bridge circuit, the impedance of the instrument measuring the output voltage must be

a. Equal to the component resistance of the circuit
b. Very large compared to the component resistance of the circuit
c. Very small compared to the component resistance
d. Less than compared to the component resistance but not very small
 Answer  Explanation  Related Ques ANSWER: Very large compared to the component resistance of the circuit Explanation: No explanation is available for this question!

8)   If the impedance of the instrument measuring the output voltage of the bridge circuit is less than the component resistance then

a. The instrument will load the bridge circuit
b. The instrument will draw current from the circuit
c. Supply current to the circuit
d. Both (a) & (b)
e. None of the above
 Answer  Explanation  Related Ques ANSWER: Both (a) & (b) Explanation: No explanation is available for this question!

9)   In a gravity controlled type indicating instrument, the current flowing through the circuit is

a. Directly proportional to the cosine of angle of deflection
b. Directly proportional to the sine of angle of deflection
c. Directly proportional to the tan of the angle of deflection
d. Directly proportional to the angle of deflection
 Answer  Explanation  Related Ques ANSWER: Directly proportional to the sine of angle of deflection Explanation: No explanation is available for this question!

10)   The scales of gravity controlled instruments are

a. Uniform
b. Non - uniform and cramped or crowded at the middle
c. Non - uniform and cramped or crowded at their lower ends
d. Non - uniform and cramped or crowded in the first half
 Answer  Explanation  Related Ques ANSWER: Non - uniform and cramped or crowded at their lower ends Explanation: No explanation is available for this question!

11)   The current sensitive instruments are

a. PMMC
b. Hot wire instruments
c. Electrostatic instruments
d. Both (a) and (b)
 Answer  Explanation  Related Ques ANSWER: Both (a) and (b) Explanation: No explanation is available for this question!

12)   Power consumption in permanent magnet moving coil instrument and hot - wire instruments are

a. Low, low
b. Low, high
c. High, low
d. High, high
 Answer  Explanation  Related Ques ANSWER: Low, high Explanation: No explanation is available for this question!

13)   In the given frequency range, which type of instrument will have highest accuracy

a. electrodynamometer
b. hot - wire instrument
c. electrostatic instrument
d. PMMC
 Answer  Explanation  Related Ques ANSWER: electrodynamometer Explanation: No explanation is available for this question!

14)   Megger is a portable instrument. It is used for the measurement of

a. Low inductance
b. Low resistance
c. High inductance
d. High resistance
 Answer  Explanation  Related Ques ANSWER: High resistance Explanation: No explanation is available for this question!

15)   In a portable instrument, the effect of stray magnetic field on actuating torque will be maximum when the operating field and stray fields are

a. Parallel to each other
b. Perpendicular to each other
c. Inclined at 45 degree
d. Opposite to each other
 Answer  Explanation  Related Ques ANSWER: Parallel to each other Explanation: No explanation is available for this question!

16)   The thermocouple instruments works on the principle of Seebeck effect. The amount of heat produced is

a. Directly proportional to the current
b. Directly proportional to the square of current
c. Inversely proportional to the current
d. Inversely proportional to the square of current
 Answer  Explanation  Related Ques ANSWER: Directly proportional to the square of current Explanation: No explanation is available for this question!

17)   The thermocouple ammeter scale is

a. Linear
b. Cramped at low end and open at high end
c. Open at low end and cramped at high end
d. Cramped at the middle
 Answer  Explanation  Related Ques ANSWER: Cramped at low end and open at high end Explanation: No explanation is available for this question!

18)   The heater wire of thermocouple instruments are made of smaller area of cross section to

a. reduce the skin effect
b. reduce temperature error
c. reduce frequency error
d. increase inductance
 Answer  Explanation  Related Ques ANSWER: reduce the skin effect Explanation: No explanation is available for this question!

19)   In a Wheatstone bridge, if P = 10 ± 1%, Q = 100 ± 1%, R = 20 ± 1% and S is unknown then the unknown resistance will be

a. 200 ± 1%
b. 200 ± 2%
c. 200 ± 3%
d. 100 ± 1%
 Answer  Explanation  Related Ques ANSWER: 200 ± 3% Explanation: No explanation is available for this question!

20)   A highly sensitive galvanometer is used in Wheatstone bridge and it can detect a current as low as 80 pA. The resistances of each arm of bridge are 800 ohm and the resistance of galvanometer is 40 ohm. If an input of 20 V is applied to the bridge then the smallest change in resistance which can be detected is

a. 10.752 μA
b. 15.280 μA
c. 17.351 μA
d. 23.719 μA
 Answer  Explanation  Related Ques ANSWER: 10.752 μA Explanation: No explanation is available for this question!

21)   The method / methods suitable for the measurement of low resistance is / are

a. Ammeter - voltmeter method
b. Kelvin’s double bridge method
c. Potentiometer method
d. All of these
 Answer  Explanation  Related Ques ANSWER: All of these Explanation: No explanation is available for this question!

22)   The bridge suitable for the measurement of capacitance is / are

a. Anderson’s bridge
b. Hay’s bridge
c. Owen’s bridge
d. None of these
 Answer  Explanation  Related Ques ANSWER: None of these Explanation: No explanation is available for this question!

23)   Schering bridges are used for the measurement of

a. Unknown capacitance
b. Dielectric loss
c. Power factor
d. All of these
e. None of these
 Answer  Explanation  Related Ques ANSWER: All of these Explanation: No explanation is available for this question!

24)   The AC Bridge which is used for the measurement of frequency is

a. Schering bridge
b. Wien bridge
c. Hay’s bridge
d. Anderson bridge
 Answer  Explanation  Related Ques ANSWER: Wien bridge Explanation: No explanation is available for this question!

25)   In L - C connected wattmeter, compensated coil is used. The error in the wattmeter is due to power consumed by the

a. Current coil
b. Potential coil
c. Inductor
d. Capacitor
 Answer  Explanation  Related Ques ANSWER: Potential coil Explanation: No explanation is available for this question!

26)   The full scale current of a galvanometer with internal resistance of 800 ohm is 8 A. what will be the multiplying power of 80 ohm shunt with this galvanometer?

a. 8
b. 9
c. 10
d. 11
 Answer  Explanation  Related Ques ANSWER: 11 Explanation: No explanation is available for this question!

27)   If the reading of the two wattmeters is equal and opposite while measuring power in a 3 phase induction motor then the power factor of the load will be

a. Unity
b. Zero
c. 0.5 lagging
 Answer  Explanation  Related Ques ANSWER: Zero Explanation: No explanation is available for this question!

28)   During load test on 3 phase induction motor, the readings of the two wattmeters are -5.5 kW and +12.5 kW respectively. If the line voltage is 420 V then the line current will be

a. 38.91 A
b. 41.02 A
c. 42.10 A
d. 43.94 A
 Answer  Explanation  Related Ques ANSWER: 43.94 A Explanation: No explanation is available for this question!

29)   The transformer ratio of the transformer depends upon the

a. Exciting current
b. Secondary current
c. Power factor of secondary circuit
d. All of these
 Answer  Explanation  Related Ques ANSWER: All of these Explanation: No explanation is available for this question!

30)   Primary current in a current transformer is determined by

a. The load on the system
b. The load on its own secondary
c. The load on its own primary
d. All of these
 Answer  Explanation  Related Ques ANSWER: The load on the system Explanation: No explanation is available for this question!

31)   If at one end, the two wires made of different metals are joined together then a voltage will get produced between the two wires due to difference of temp between the two ends of wires. This effect is observed in

a. Thermocouples
b. Thermistors
c. RTD
d. Ultrasonics
 Answer  Explanation  Related Ques ANSWER: Thermocouples Explanation: No explanation is available for this question!

32)   For the measurement of pressure the instruments used can be

a. Mechanical
b. Electro - mechanical
c. Electronic
d. All of these
e. None of these
 Answer  Explanation  Related Ques ANSWER: All of these Explanation: No explanation is available for this question!

33)   With the increase in the intensity of light, the resistance of a photovoltaic cell

a. Increases
b. Decreases
c. Remains same
d. None of these
 Answer  Explanation  Related Ques ANSWER: Decreases Explanation: No explanation is available for this question!

34)   Contact devices used for the measurement of level are

a. Less reliable then devices which does not make contact with the material
b. More reliable then devices which does not make contact with the material
c. Less reliable then devices which makes contact with the material
d. More reliable then devices which makes contact with the material
 Answer  Explanation  Related Ques ANSWER: Less reliable then devices which does not make contact with the material Explanation: No explanation is available for this question!

35)   Instrument which is capable of discriminating temperature differences of even 0.1 degree Celsius is

a. Fibre - optic level sensors
b. Laser method
c. Thermography
d. Vibrating level sensors
 Answer  Explanation  Related Ques ANSWER: Thermography Explanation: No explanation is available for this question!

36)   In fibre - optic level sensors, the amount of light loss depends on

a. The proportion of cable that is submerged in the liquid
b. Amount of light which is reflected back
c. The proportion of cable that is not in the liquid
d. Amount of light which is not reflected back
 Answer  Explanation  Related Ques ANSWER: The proportion of cable that is submerged in the liquid Explanation: No explanation is available for this question!

37)   The displacement measuring instruments is / are

a. Potentiometer
b. LVDT
c. RVDT
d. All of these
 Answer  Explanation  Related Ques ANSWER: All of these Explanation: No explanation is available for this question!

38)   Potentiometer is used for the measurement of

a. Linear displacement
b. Angular displacement
c. Non - linear displacement
d. Only (1) and (2)
e. All the above
 Answer  Explanation  Related Ques ANSWER: Only (1) and (2) Explanation: No explanation is available for this question!

39)   The measurements which can be simplified by using X - Y recorders is / are

a. Speed - torque characteristics of motors
b. Regulation curves of power supplies
c. Hysteresis curves
d. All of these
 Answer  Explanation  Related Ques ANSWER: All of these Explanation: No explanation is available for this question!

40)   Depending on whether the display is a numeric or alphanumeric, the segmental display is

a. 7 segmental
b. 14 segmental
c. 21 segmental
d. Either (a) or (b)
e. None of the above
 Answer  Explanation  Related Ques ANSWER: Either (a) or (b) Explanation: No explanation is available for this question!