ELECTRICAL ENGINEERING IMPORTANT MCQ-BASIC ELECTRICAL PART FOUR

ANSWER KEY-Correct
answer is indicated by symbol (V) in options.
HINTS-In some questions options
E-HINTS is indicating the hints of answer.

51) If a resistor and an inductor are connected in series across a voltage source. Which
two parameters in that circuit decrease if frequency of voltage source increases?
A [ ]) VL and Z.
B [v]) VR and I.
C [ ]) Z and I.
D [ ]) VL and VR.

52) If a resistor and a capacitor are connected to form series R – C circuit across a voltage
source. If frequency of voltage source increases
A [v]) the current increases.
B [ ]) the current decreases.
C [ ]) the current remain unaltered.
D [ ]) the current decreases abruptly.

53) Which of the following characteristics is attributed to an ideal independent voltage
source?
A [v]) Independent of magnitude of current supplied.
B [ ]) Dependent of the magnitude of current supplied.
C [ ]) Dependent of the direction of flow of current.
D [ ]) None of above.

54) With some initial change at t = 0+, a capacitor will act as
A [ ]) short circuit.
B [ ]) open circuit.
C [v]) a voltage source.
D [ ]) a current source.

55) i) In star connection line current is equal to phase current.
ii) In delta connection line voltage is equal to phase voltage.
For a given phase connected to the particular line which of the statement is true ?
A [ ]) Only (1).
B [ ]) Only (2).
C [v]) Both (A) and (B).
D [ ]) None of these.

56) A 3 -PHASE delta connected symmetrical load consumes P Watts of power from a
balanced supply. If the same load is connected in star to the same supply then what is the
power consumption?
A [v]) P / 3.
B [ ]) P.
C [ ]) 3P.
D [ ]) NONE

57) For a 3 – phase load balanced condition, each phase has the same value of
A [ ]) impedance.
B [ ]) resistance.
C [ ]) power factor.
D [v]) all of these.

58) In delta connected circuit when one resistor is open, then power will be
A [ ]) 0.
B [ ]) increased by factor of 3.
C [v]) reduced by the factor of 3.
D [ ]) remain unchanged.

59) In a highly capacitive circuit
A [ ]) actual power is more than its reactive power
B [v]) reactive power is more than actual power
C [ ]) reactive power is more than apparent power
D [ ]) apparent power is equal to the actual power

60) The peak factor of a triangular ac voltage wave is
A [ ]) 1
B [ ]) 1.11
C [ ]) 1.41
D [v]) 1.732

61) The right hand rule for determining the direction of the induced EMF was introduced by
A [ ]) Faraday
B [ ]) Lenz
C [v]) Fleming
D [ ]) Maxwell

62) Whenever the magnetic flux changes with respect to an electric conductor or a coil, an
EMF is induced in the conductor is Faraday’s
A [v]) first law
B [ ]) second law
C [ ]) third law
D [ ]) fourth law

63) Which of the following represents ohms law
A [ ]) V = RI
B [ ]) J = σE
C [ ]) I = GV
D [v]) All of the above

64) Conductor is constant and field is varying then emf will induce. This principle is called
A [ ]) virtually induced emf.
B [ ]) dynamically induced emf.
C [v]) static induced emf.
D [ ]) none of these

65) In the left hand rule, forefinger always represents
A [ ]) voltage.
B [ ]) current.
C [v]) magnetic field.
D [ ]) direction of force on the conductor.

66) Cork Screw rule is used to find
A [ ]) direction of current.
B [v]) direction of magnetic field.
C [ ]) direction of electric field.
D [ ]) direction of emf.

67) Biot-Savarts law states the relation between magnetic intensity and
A [ ]) filament current only.
B [ ]) surface current only.
C [v]) volume current only.
D [ ]) (A), (B), and (C) are all correct.

68) According to Coulomb’s law, the force of attraction or repulsion, between to electrical
charges is
A [ ]) directly proportional to the square of the distance between them.
B [ ]) inversely proportional to the square of the distance between them.
C [v]) inversely proportional to the distance between them.
D [ ]) directly proportional to the distance between them.

69) Ohm’s law in point from field theory can be expressed as
A [v]) J = σE.
B [ ]) V = IR.
C [ ]) J = E / σ.
D [ ]) R = ρ × ( l / A).

70) It was suggested by _____________ that the electric field should be imagined to be
divided into tubes of force containing a fixed number of line of force
A [ ]) Kelvin.
B [v]) Faraday.
C [ ]) Newton.
D [ ]) all of above.

71) The Biot-savarts law is a general modification of
A [ ]) Kirchhoffs law.
B [ ]) Lenzs law.
C [v]) Amperes law.
D [ ]) Faradays law.

72) The direction of induced emf can be found by
A [ ]) Laplaces law.
B [ ]) Kirchhoffs voltage law.
C [v]) Lenzs law.
D [ ]) Flemings right hand rule.

73) Conductor is varying and field is fixed then emf will induces. This principle is called
A [v]) dynamically induced emf.
B [ ]) static induced emf.
C [ ]) both A and B.
D [ ]) none of the above.

74) Flemings left hand rule may be applied to an electric generator to find out the direction
of
A [v]) induced emf.
B [ ]) rotor rotation.
C [ ]) magnetic field.
D [ ]) none of the above.

75) Which of the following is not the same as watt?
A [ ]) joule/sec
B [v]) amperes/volt
C [ ]) amperes x volts
D [ ]) ( amperes )² x ohm.

76) When P = Power, V = Voltage, I = Current, R = Resistance and G = Conductance, which
of the following relation is incorrect?
A [ ]) V = √ (PR)
B [ ]) P= V²G
C [v]) G= P / I²
D [ ]) I =√ (P / R)

77) The unit of electrical conductivity is
A [v]) mho / metre
B [ ]) mho / sq. m
C [ ]) ohm / metre
D [ ]) ohm / sq. m.

78) How many different combinations may be obtained with three resistors, each having
the resistance R ?
A [ ]) 3
B [v]) 4
C [ ]) 5
D [ ]) 6

79) Ohm’s law is not applicable to
A [ ]) DC circuits
B [ ]) high currents
C [ ]) small resistors
D [v]) semi-conductors.

80) A metal resistor has resistance of 10 ohm at 0°C and 11 ohms at 160°C, the temperature
coefficient is
A [ ]) 0.00625 / °C
B [ ]) 0.0625 /°C
C [v]) 0.000625 /°C
D [ ]) 0.625 /°C.

81) Ohm’s law is not applicable in all the following cases Except
A [ ]) Electrolytes
B [ ]) Arc lamps
C [v]) Insulators
D [ ]) Vacuum ratio values.

82) Which of the following has negative temperature coefficient ?
A [ ]) Brass
B [ ]) Mercury
C [v]) Electrolytes
D [ ]) Silver.

83) Variable resistors are
A [v]) Wire wound resistors
B [ ]) Thin film resistors
C [ ]) Thick film resistors
D [ ]) All of the above.

84) Temperature coefficient of resistance is expressed in terms of
A [v]) ohms / ohms oC
B [ ]) mhos / ohm oC
C [ ]) mhos / oC
D [ ]) ohms / oC.

85) A fuse is always installed in a circuit is
A [v]) Series
B [ ]) Parallel.
C [ ]) either series or Parallel.
D [ ]) both

86) The rating of fuse wire is expressed in terms of
A [ ]) Ohms
B [ ]) Mhos
C [v]) Amperes
D [ ]) Watts.

87) The current carrying capacity of the fuse material depends on
A [ ]) cross-sectional area
B [ ]) length
C [ ]) material
D [v]) all of the above.

88) ccording to the fuse law, the current carrying capacity varies as
A [ ]) diameter
B [v]) (diameter)³⁄²
C [ ]) 1 / diameter
D [ ]) )1 / (diameter)²

89) In the color code white color represents the number
A [v]) 9
B [ ]) 8
C [ ]) 7
D [ ]) 6
E [ ]) 5

90) Production of heat due to current is related by which law
A [ ]) Ohm’s law
B [v]) Joule’s law
C [ ]) Kelvin’s law
D [ ]) Maxwell’s law.

91) A rheostat differs from potentiometer in the respect that
A [ ]) rheostat has large number of turns
B [ ]) rheostat offers larger number of tappings
C [ ]) rheostat has lower wattage rating
D [v]) rheostat has higher wattage ratings.

92) Which of the following has negative coefficient of resistance?
A [ ]) Wire wound resistor
B [ ]) Metals
C [ ]) Non-metals
D [v]) Thermistor.

93) Certain substances lose their electrical resistance completely at finite low
temperatures. Such substances are called
A [ ]) dielectrics
B [v]) super-conductors
C [ ]) semi conductors
D [ ]) perfect conductors.

94) In a carbon resistor in case fourth stripe is not present, it can be concluded that
A [ ]) the resistor is highly accurate
B [ ]) the resistor is defective
C [ ]) the resistor does not contain carbon
D [v]) the tolerance limit is ± 20 %.

95) In a nickel-cadmium-alkali cell the electrolyte is
A [ ]) sulphur acid
B [v]) potassium hydroxide
C [ ]) zinc chloride
D [ ]) ammonium chloride.

96) All good conductors have high
A [ ]) resistance
B [ ]) electrical conductivity
C [ ]) electrical and thermal conductivity
D [v]) conductance.

97) A light dependent resistor is basically a
A [ ]) power resistor
B [ ]) non-metallic resistor
C [ ]) carbon resistor
D [v]) variable resistor.

98) Voltage dependent resistors are usually made from
A [ ]) graphite
B [ ]) charcoal
C [v]) silicon carbide
D [ ]) nichrome.

99) Metals approach super-conductivity conditions
A [v]) near absolute zero temperature
B [ ]) near critical temperature
C [ ]) at triple point
D [ ]) under the conditions of high temperature and pressure.

100) Voltage dependent resistors are used
A [ ]) as current stabilizers
B [ ]) as heating elements
C [ ]) for inductive circuits
D [v]) to suppress surges.
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