Electrical and Electronics Measurement & Instrumentation Expected MCQ PDF 8 For VIZAG Exam 2017

1)   In a moving coil voltmeter, the input resistance of the meter can be increased by
a. Increasing the number of turns in the coil
b. Decreasing the number of turns in the coil
c. Using the same number of coil turns made up of high resistance material
d. Both (a) & (c)

ANSWER: Both (a) & (c)
2)   The magnitude of environment – induced variation from the specified calibration condition is quantified by
a. Sensitivity drift
b. Zero drift
c. Backlash
d. Both (a) & (b)

ANSWER: Both (a) & (b)
3)   The systematic errors of an instrument can be reduced by making
a. The sensitivity of instrument to environmental input as low as possible
b. The sensitivity of instrument to environmental input as high as possible
c. Systematic errors does not depend on the sensitivity of instrument
d. None of these

ANSWER: The sensitivity of instrument to environmental input as low as possible
4)   Suitable method for the reduction of systematic errors is / are
a. Instrument must be designed carefully
b. By introducing an equal and
opposite environmental input for compensating the effect of
environmental input in a measurement system
c. By adding high gain feedback to measurement system
d. All of these

ANSWER: All of these
5)   If the instrument is used in wrong manner while application, then it will results in
a. Systematic error
b. Instrument error
c. Random error
d. Environmental error

ANSWER: Instrument error
6)   The undesirable characteristics of a measuring system is / are
a. Drift
b. Dead zone
c. Non linearity
d. All of these

ANSWER: All of these
7)   Calibration
of instrument is an important consideration in measurement system. The
errors due to instruments being out of calibration can be rectified by

a. Increasing the frequency of recalibration
b. Increasing the temperature coefficient
c. Increasing the susceptibility of measuring instrument
d. Decreasing the frequency of recalibration

ANSWER: Increasing the frequency of recalibration
8)   Random errors in a measurement system are due to
a. Environmental changes
b. Use of uncalibrated instrument
c. Poor cabling practices
d. Unpredictable effects

ANSWER: Unpredictable effects
9)   The gravity controlled instruments has to be kept
a. Vertical
b. Horizontal
c. Inclined at 45 degree
d. Inclined at 75 degree

ANSWER: Vertical
10)   A deflection
of 90 degree is produced when a current of 10 A flows through the
circuit and the torque of the ammeter vary as the square of the current
through it. If a current of 8 A flows through it, then the deflection
obtained when the instrument is spring controlled and when the
instrument is gravity controlled are

a. 39.79 degree, 57.6 degree
b. 47.55 degree, 35.67 degree
c. 57.6 degree, 39.79 degree
d. 35.67 degree, 47.55 degree

ANSWER: 57.6 degree, 39.79 degree
11)   Damping torque is the torque which acts on
a. Stationary system of the instrument
b. Moving system of the instrument only when it is stationary
c. Moving system of the instrument only when it is moving
d. Stationary system of the instrument only when the moving system is moving

ANSWER: Moving system of the instrument only when it is moving
12)   Induction type instruments are generally used as
a. Ammeter
b. Voltmeter
c. Wattmeter
d. All of these
e. None of these

ANSWER: All of these
13)   A cylindrical type with split phase winding induction ammeters employs
a. A rotating disc
b. A hollow aluminium drum
c. A single flux producing winding
d. Either (a) or (b)

ANSWER: A hollow aluminium drum
14)   In induction voltmeter, split phase windings are obtained by connecting a
a. High resistances in series with windings of both the magnets
b. High resistance in series with the winding of one magnet and an inductive coil in series with the windings of other magnet
c. An inductive coil in series with the winding of one magnet and a capacitance in series with the windings of other magnet
d. Inductive coils in series with the winding of both the magnets

ANSWER:
High resistance in series with the winding of one magnet and an
inductive coil in series with the windings of other magnet
15)   For reducing the errors in an induction instrument the alternating current to be measured has
a. Same frequency with which the instrument was calibrated
b. High frequency compared with which the instrument was calibrated
c. Low frequency compared with which the instrument was calibrated
d. None of these

ANSWER: Same frequency with which the instrument was calibrated
16)   The frequency errors in induction instruments can be compensated by the use of
a. Non inductive shunt in both ammeters and voltmeters
b. Non inductive shunt in case of ammeters and are generally self compensated in case of voltmeters
c. Self compensated in case of both ammeters and voltmeters
d. Self compensated in case of ammeters and non inductive shunt in case of voltmeters

ANSWER: Non inductive shunt in case of ammeters and are generally self compensated in case of voltmeters
17)   The temperature errors in induction instruments can be compensated by
a. Hunting in both ammeters and voltmeters
b. Combination of shunt and swamping resistance in both ammeters and voltmeters
c. Hunting in case of ammeters and Combination of shunt and swamping resistance in case of voltmeters
d. Combination of shunt and swamping resistance in case of ammeters and hunting in case of voltmeters

ANSWER: Hunting in case of ammeters and Combination of shunt and swamping resistance in case of voltmeters
18)   Which among the following is not true about the induction instruments?
a. It can be used for ac measurements only
b. Damping is very efficient in case of induction instruments
c. Compensation for frequency temperature is not required
d. Cost is relatively high

ANSWER: Compensation for frequency temperature is not required
19)   In a moving coil of a meter swamping resistance is added to
a. Reduce the frequency error
b. Reduce the temperature error
c. Reduce the power consumption
d. All of these

ANSWER: Reduce the temperature error
20)   Swamping resistance is a resistance made up of
a. Alloy of manganin and copper
b. Alloy of aluminium and copper
c. Alloy of nickel and cobalt
d. Alloy of manganin and aluminium

ANSWER: Alloy of manganin and copper
21)   For the measurement of low resistances, Kelvin’s double bridge has high accuracy because
a. It has two set of ratio arms which eliminates effect of resistance of connecting lead
b. It has a null indicating galvanometer
c. It has two null indicator
d. It has four sets of ratio arms which eliminates the effect of resistance of connecting lead

ANSWER: It has two set of ratio arms which eliminates effect of resistance of connecting lead
22)   For the
measurement of low resistances from few ohms down to one micro ohm,
which of the following instrument is not suitable?

a. Potentiometer method
b. Ammeter – voltmeter method
c. Ohmmeter
d. Kelvin double bridge method

ANSWER: Ohmmeter
23)   In a slide
wire potentiometer, for a voltage source of 1.012 V the jockey is kept
at 101.2 cm. If the potentiometer has 20 wires of 1 m each and the
resistance of wires is 800 ohm, then the value of the working current is

a. 15 mA
b. 20 mA
c. 25 mA
d. 27 mA

ANSWER: 25 mA
24)   The Wien’s bridges is suitable for the measurement of frequency of the range of
a. Less than 100 Hz
b. 100 Hz to 100 kHz
c. 1 kHz to 100 MHz
d. More than 100 MHz

ANSWER: 100 Hz to 100 kHz
25)   For the measurement of unknown inductance in terms of known capacitance, the suitable ac bridges are
a. Maxwell and Schering bridge
b. Maxwell and Wien’s bridge
c. Maxwell and Hay’s bridge
d. Hay’s and Wien’s bridge

ANSWER: Maxwell and Hay’s bridge
26)   If a
capacitor is connected across a portion of resistance of multiplier of
the wattmeter then the pressure coil of the circuit becomes

a. Inductive
b. Non inductive
c. Capacitive
d. Non capacitive

ANSWER: Non inductive
27)   The two
wattmeters used for the measurement of power input read 50 kW each. What
will be the readings of the two wattmeters if the power factor is
changed to 0.8 leading keeping the total input power same?

a. 28.35W, 71.65W
b. 31.25W, 73.71W
c. 33.33W, 73.33W
d. 38.35W, 75.5W

ANSWER: 28.35W, 71.65W
28)   Ballistic galvanometer are principally used for the measurement of
a. Current
b. Voltage
c. Power
d. Electric charges

ANSWER: Electric charges
29)   Vibration galvanometer are generally used
a. For measuring electric charges
b. As null – point detectors in ac bridges
c. As null – point detectors in dc bridges
d. For measuring power

ANSWER: As null – point detectors in ac bridges
30)   The meter of a vibrating reed frequency meter depends for its indications on the
a. Electrical resonance of thin flat steel reeds
b. Mechanical resonance of thin flat steel reeds
c. Mechanical resonance of thick flat steel reeds
d. Electrical resonance of thick flat steel reeds

ANSWER: Mechanical resonance of thin flat steel reeds
31)   The potential transformers are used to measure large voltage using
a. High range voltmeter
b. Low range voltmeter
c. High range ammeter
d. Low range ammeter

ANSWER: Low range voltmeter
32)   If an instrument transformer is used to extend the ranges of AC instrument, then its reading will depend on
a. R
b. L
c. C
d. All of these
e. None of these

ANSWER: None of these
33)   If the displacement is measured with strain gauge then the number of strain gauge normally required are
a. One
b. Two
c. Three
d. Four

ANSWER: Four
34)   A capacitive pressure sensor has a typical measurement uncertainty of
a. ± 0.2%
b. ± 0.4%
c. ± 0.1%
d. ± 0.8%

ANSWER: ± 0.2%
35)   The instruments used for the measurement of pressure is / are
a. Bellows
b. Diaphragms
c. Fiber optic pressure sensors
d. All of these
e. None of the above

ANSWER: All of these
36)   LVDT which is an instrument for the measurement of displacement, works on the principal of
a. Linear inductance
b. Non – linear inductance
c. Mutual inductance
d. Linear capacitance

ANSWER: Mutual inductance
37)   In rotary
variable differential transformer, the mutual inductance between the
primary and secondary coils varies

a. Linearly with the angular displacement
b. Non – linearly with the angular displacement
c. Linearly with the linear displacement
d. Non – linearly with the linear displacement

ANSWER: Linearly with the angular displacement
38)   Resolver works on the principal of mutual inductance variation. It is mainly used for the measurement of
a. Linear displacement
b. Non – linear displacement
c. Rotary motion
d. All of these

ANSWER: Rotary motion
39)   In light emitting diode, the available light emitting region is
a. Less than 2.5 mm
b. From 2.5 to 25 mm
c. Greater than 25 mm
d. Greater than 50 mm

ANSWER: From 2.5 to 25 mm
40)   In liquid crystal displays, the liquid crystal exhibits properties of
a. Liquid
b. Solids
c. Gases
d. Both (a) and (b)

ANSWER: Both (a) and (b)


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Electrical and Electronics Measurement & Instrumentation Expected MCQ PDF 7 For VIZAG Exam 2017

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