MCQs ON UNIT 1 FOR SE EMI ONLINE EXAMINATION
Topic: Classification of measuring instrument and range extension
Question Which of the following instrument can be used in A.C. bridges for less frequencies up to
200 Hz only
A Head phone
B Tunable amplifier detector
C Vibration galvanometer
D All of the above
Answer C
Question Which of the following bridge is used in strain gauge measurement
A Kelvin bridge
B Specially design bridge
C Kelvin double bridge
D Carey-foster bridge
Answer B
Question A Megger is basically a
A Moving iron type instrument
B Moving coil type instrument
C Hot wire instrument
D Electrolytic instrument
Answer B
Question Maxwell inductance capacitance bridge is used for measurement of inductance of
A Low Q coils only
B Medium Q coils only
C High Q coils only
D Low and Medium Q coils only
Answer B
Marks 2
Unit 1
Topic: Topic: Classification of measuring instrument and range extension
Question 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
Question Loss of charge method is used to measure
A Low Resistance
B High Resistance
C Low Inductance
D High Inductance
Answer B
Question 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
Question Anderson bridge is used to measure of:
A Inductance
B Capacitance
C Time period
D Resistance and capacitance
Answer A
Marks 2
Unit 1
Topic: Topic: Classification of measuring instrument and range extension
Question Kelvin double bridge is best suited for the measurement of:
A Inductance
B Capacitance
C Low resistance
D High resistance
Answer C
Question The material used to make standard resistance is:
A Manganin
B Aluminum
C Nichrome
D Platinum
Answer A
Question Inductance is measured by which one of the following
A Wien bridge
B Schering bridge
C Maxwell bridge
D Owen bridge
Answer C
Question If a wheat stone bridge is in balance condition then
A A heavy current flows through the galvanometer
B No current flows through the galvanometer
C The current in each of the four arms R1, R2, R3 and R4 are same
D A low current flows through the galvanometer
Answer B
Marks 2
Unit 1
Topic: Topic: Classification of measuring instrument and range extension
Question The value of resistance of an earthing electrode depends upon
A Shape and material of electrode
B Depth to which electrode is driven into earth
C Specific resistance of soil
D All of the above
Answer D
Question From the point of view of safety, the resistance of earthing electrode should be
A Low
B High
C Medium
D The value of resistance of earth electrode does not affect the safety
Answer A
Question ------------- is a instrument which measures the insulation resistance of an electrical circuit
relative to earth and one another
A Tangent galvanometer
B Megger
C Current transformer
D None of the above
Answer B
Question The controlling torque in a megger is provided by
A Springs
B Weights attached to the moving system
C It does not need any controlling torque
D None of the above
Answer C
Marks 2
Unit 1
Topic: Topic: Classification of measuring instrument and range extension
Question The operating voltage of a megger is about
A 6V
B 120V
C 400V
D 500V
Answer D
Question The electrical power to a megger is provided by
A Battery
B Permanent magnet DC generator
C A.C generator
D Any of the above
Answer B
Question For measuring a very high resistance we should use
A Kelvins double bridge
B Wheatstone bridge
C Megger
D None of the above
Answer C
Marks 2
Unit 1
Topic: Topic: Classification of measuring instrument and range extension
Question A bride circuit works at a frequency of 2 kHz. The following can be used as detectors for
detection of null conditions in the bridge
A Vibration galvanometer and head phones
B Head phones and tunable amplifiers
C Vibration galvanometer and tunable amplifiers
D Vibration galvanometer, head phones and tunable amplifiers
Answer B
Topic: Topic: Classification of measuring instrument and range extension
Question The nominal ratio of a current transformer is
A Primary winding current/ Secondary winding current
B Rated primary winding current/ Rated secondary winding current
C Number of secondary winding turns / Number of turns of primary winding turns
D All of the above
Answer B
Question The transformation ratio in the case of a potential transformer is defined as the
A Primary winding voltage / Secondary winding voltage
B Rated primary winding voltage / Rated secondary winding voltage
C Number of turns of primary winding turns/ Number of turns of secondary winding turns
D All of the above
Answer A
Question The ratio and phase angle error in potential transformers may be reduced by
A Increasing the exciting current
B Increasing the resistance and leakage reactance in the transformer
C By not employing turns compensation
D None of the above
Answer D
Question Turns compensation is used in current transformers primarily for reduction of
A Phase angle error
B Both ratio and phase angle error
C Ratio error, reduction in phase angle error is incidental
D None of the above
Answer C
Marks 2
Unit 1
Topic: Topic: Classification of measuring instrument and range extension
Question When the secondary winding of a potential transformer is suddenly open circuited with
primary winding excited
A Large voltages are produced in the secondary winding may be a safety hazard to operating
person
B Large voltages so produced may rupture the insulation
C The primary winding draws only the no load current
D None of the above
Answer C
Question The burden of current transformers is expressed in terms of
A Secondary winding current
B VA rating of transformer
C Voltage, current and power factor of secondary winding circuit
D None of the above
Answer B
Question The error in current transformers can be reduced by designing them with
A High permeability and low loss core materials, avoiding any joints in the core and keeping
flux density to a low values
B Using primary and secondary windings as close to each other as possible
C Using large cross-sections for both primary and secondary winding conductors
D All of the above
Answer A
Question An instrument transformer is used to extend the range of
A Induction instrument
B Electrostatic instrument
C Moving coil instrument
D All of the above
Answer A
Marks 2
Unit 1
Topic: Topic: Classification of measuring instrument and range extension
Question A multi range instrument has
A Multiple shunt or series resistances inside the meter
B Multi coil arrangement
C Variable turns of coil
D All of the above
Answer A
Question Standard resister is made from
A Platinum
B Maganin
C Silver
D Nichrome
Answer B
Question The multiplier and the meter coil in a voltmeter are in
A Series
B Parallel
C Series- Parallel
D None of the above
Answer A
Question The function of shunt in an ammeter is to
A By pass the current
B Increase the sensitivity of ammeter
C Increase the resistance of ammeter
D None of the above
Answer A
Marks 2
Unit 1
Topic: Topic: Classification of measuring instrument and range extension
Question The chemical effect of current is used in
A D.C ammeter hour meter
B D.C ammeter
C D.C energy meter
D None of the above
Answer A
Question Which of the following is used for extending the range of instrument
A Shunt
B Multiplier
C Current transformer
D All of the above
Answer D
Question Which of the following essential features is possessed by an indicating instrument
A Deflecting device
B Controlling device
C Damping device
D All of the above
Answer D
Question The burden of current transformers is expressed in terms of
A Secondary winding currents
B VA rating of transformer
C Voltage, current, power factor of secondary winding
D None of the above
Answer B
Marks 2
Unit 1
Topic: Topic: Classification of measuring instrument and range extension
Question Instrument is a device for determining
A The magnitude of a quantity
B The physics of a variable
C Either of the above
D Both (a) and (b)
Answer A
Question Electronic instruments are preferred because they have
A No indicating part
B Low resistance in parallel circuit
C Very fast response
D High resistance in series circuit
Answer A
Question A DC wattmeter essentially consist of
A Two ammeters
B Two voltmeters
C A voltmeter and an ammeter
D A current and potential transformer
Answer C
Question An accurate voltmeter must have an internal impedance of
A Very low value
B Low value
C Medium value
D Very high value
Answer D
Marks 2
Unit 1
Topic: Topic: Classification of measuring instrument and range extension
Question A 100 V voltmeter has full-scale accuracy of 5%. At its reading of 50 V it will give an
error of
A 10%
B 5%
C 2.5%
D 1.25%
Answer
Question Transformers used in conjunction with measuring instruments for measuring purposes are
called
A Measuring transformers
B Transformer meters
C Power transformers
D Instrument transformers
Answer D
Question The rating of instrument transformer may be expressed in
A kW
B kVAR
C kVA
D Horse power
Answer C
Question Continuous recording of a signal is not possible in a
A magnetic tape recorder
B strip chart recorder
C X-Y recorder
D Galvanometric recorder
Answer A
Marks 2
Unit 1
Topic: Topic: Classification of measuring instrument and range extension
Question The errors introduced by an instrument fall in which category
A Systematic errors
B Random errors
C Gross errors
D Environmental errors
Answer C
Question Which one of the following instruments is commonly used to measure primary current of a
transformer connected to mains
A Electrostatic meter
B Current transformer
C Moving coil type meter
D Moving iron meter
Answer C
Question How can a milli-ammeter be used as a voltmeter
A By connecting a low resistance in parallel with the instrument
B By connecting a high resistance in parallel with the instrument
C By connecting a low resistance in series with the instrument
D By connecting a high resistance in series with the instrument
Answer A
Question Due to which one of the following reasons bearing of PMMC
Instrument are made of Jewel
A To avoid wear and tear of the moving system
B To provide a small support
C It can be easily replaced
D To make the system robust
Answer A
Marks 2
Unit 1
