# Electrical and Electronics Measurement & Instrumentation Expected MCQ PDF 5 For VIZAG Exam 2017

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: Output will exhibit constant amplitude oscillation
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

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: Always disturbs the system being measured
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

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: Either all the errors will be positive or all the errors will be negative
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

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: Very large compared to the component resistance of the circuit
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

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: Directly proportional to the sine of angle of deflection
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: Non – uniform and cramped or crowded at their lower ends
11)   The current sensitive instruments are
a. PMMC
b. Hot wire instruments
c. Electrostatic instruments
d. Both (a) and (b)

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

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

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

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

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: Directly proportional to the square of current
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: Cramped at low end and open at high end
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

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%

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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: Less reliable then devices which does not make contact with the material
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

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: The proportion of cable that is submerged in the liquid
37)   The displacement measuring instruments is / are
a. Potentiometer
b. LVDT
c. RVDT
d. All of these

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

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