ELECTRICAL ENGINEERING- PAGE 1
ELECTRICAL ENGINEERING MCQs- PAGE 1
1:-Superposition Theorem is essentially based on the concept of
A:-Reciprocity
B:-Linearity
C:-Duality
D:-Non linearity
Ans: B
2:-Form factor for DC supply voltage is always
A:-Zero
B:-Unity
C:-Infinity
D:-Any value between zero and one
Ans: B
3:-In purely resistive circuits
A:-Power factor is unity
B:-Power consumed is zero
C:-Heat produced is zero
D:-Power factor is zero
Ans: A
4:-In a series resonant circuit, the impedance below resonant frequency is
A:-Capacitive
B:-Inductive
C:-Resistive
D:-Depends on values of circuit components
Ans: A
5:-The figure of merit of RLC circuit will increase if
A:-R decreases
B:-R increases
C:-Voltage increases
D:-Voltage decreases
Ans: A
6:-In an Intrinsic Semiconductor, Fermi Level represents the energy, with probability of its occupation of
A:-0 %
B:-25 %
C:-50 %
D:-100 %
Ans: C
7:-An Infra Red LED is usually fabricated from
A:-Ge
B:-Si
C:-GaAs
D:-GaAsP
Ans: C
8:-Avalanche Photo diodes are preferred over PIN diodes in optical communication systems because of
A:-Speed of operation
B:-Higher Sensitivity
C:-Larger bandwidth
D:-Larger power handling capacity
Ans: D
9:-Power Transistors are invariably provided with
A:-Heat Sink
B:-Metallic casing
C:-Soldered connections
D:-Fan for heat removal
Ans: A
10:-In a JFET, beyond Pinch Off Voltage, as the drain voltage increases, the drain current
A:-Decreases
B:-Remains constant
C:-Increases
D:-May increase or decrease
Ans: B
11:-After firing an SCR, if the gate pulse is removed, the SCR current
A:-Remains the same
B:-Reduces to zero
C:-Rises up
D:-Rise a little, then falls to zero
Ans: A
12:-One of the characteristic of the Emitter Follower is its
A:-Low input resistance
B:-Low current gain
C:-Low voltage gain
D:-High output resistance
Ans: C
13:-Cross Over Distortion in class B push pull amplifier is eliminated by
A:-Class C operation
B:-Class AB operation
C:-Elimination of output transformer
D:-Reducing transistor bias
Ans: B
14:-A high Q tuned circuit in a tuned amplifier permits it to have high
A:-Selectivity
B:-Fidelity
C:-Sensitivity
D:-Frequency range
Ans: A
15:-Which of the following Op-Amp system is non linear?
A:-Current to Voltage Converter
B:-Logarithmic Amplifier
C:-Active Filter
D:-Delay Equalizer
Ans: B
16:-At microwave frequencies, the size of the antenna becomes
A:-Very large
B:-Large
C:-Small
D:-Very small
Ans: D
17:-In a single phase full converter, the number of SCRs conducting during overlap is
A:-1
B:-2
C:-3
D:-4
Ans: D
18:-A sinusoidal voltage of amplitude 1 kV is amplitude modulated by another sinusoidal voltage to produce 30% modulation. The amplitude of each sideband term is
A:-300 volts
B:-150 volts
C:-500 volts
D:-250 volts
Ans: B
19:-An interrupt in which the external device supplies its address as well as the interrupt request is known as
A:-Vectored interrupt
B:-Maskable interrupt
C:-Non - Maskable interrupt
D:-Designated interrupt
Ans: A
20:-Logic 1 in negative logic system is represented by
A:-Zero level
B:-Lower voltage level
C:-Higher voltage level
D:-Negative voltage
Ans: B
A:-Reciprocity
B:-Linearity
C:-Duality
D:-Non linearity
Ans: B
2:-Form factor for DC supply voltage is always
A:-Zero
B:-Unity
C:-Infinity
D:-Any value between zero and one
Ans: B
3:-In purely resistive circuits
A:-Power factor is unity
B:-Power consumed is zero
C:-Heat produced is zero
D:-Power factor is zero
Ans: A
4:-In a series resonant circuit, the impedance below resonant frequency is
A:-Capacitive
B:-Inductive
C:-Resistive
D:-Depends on values of circuit components
Ans: A
5:-The figure of merit of RLC circuit will increase if
A:-R decreases
B:-R increases
C:-Voltage increases
D:-Voltage decreases
Ans: A
6:-In an Intrinsic Semiconductor, Fermi Level represents the energy, with probability of its occupation of
A:-0 %
B:-25 %
C:-50 %
D:-100 %
Ans: C
7:-An Infra Red LED is usually fabricated from
A:-Ge
B:-Si
C:-GaAs
D:-GaAsP
Ans: C
8:-Avalanche Photo diodes are preferred over PIN diodes in optical communication systems because of
A:-Speed of operation
B:-Higher Sensitivity
C:-Larger bandwidth
D:-Larger power handling capacity
Ans: D
9:-Power Transistors are invariably provided with
A:-Heat Sink
B:-Metallic casing
C:-Soldered connections
D:-Fan for heat removal
Ans: A
10:-In a JFET, beyond Pinch Off Voltage, as the drain voltage increases, the drain current
A:-Decreases
B:-Remains constant
C:-Increases
D:-May increase or decrease
Ans: B
11:-After firing an SCR, if the gate pulse is removed, the SCR current
A:-Remains the same
B:-Reduces to zero
C:-Rises up
D:-Rise a little, then falls to zero
Ans: A
12:-One of the characteristic of the Emitter Follower is its
A:-Low input resistance
B:-Low current gain
C:-Low voltage gain
D:-High output resistance
Ans: C
13:-Cross Over Distortion in class B push pull amplifier is eliminated by
A:-Class C operation
B:-Class AB operation
C:-Elimination of output transformer
D:-Reducing transistor bias
Ans: B
14:-A high Q tuned circuit in a tuned amplifier permits it to have high
A:-Selectivity
B:-Fidelity
C:-Sensitivity
D:-Frequency range
Ans: A
15:-Which of the following Op-Amp system is non linear?
A:-Current to Voltage Converter
B:-Logarithmic Amplifier
C:-Active Filter
D:-Delay Equalizer
Ans: B
16:-At microwave frequencies, the size of the antenna becomes
A:-Very large
B:-Large
C:-Small
D:-Very small
Ans: D
17:-In a single phase full converter, the number of SCRs conducting during overlap is
A:-1
B:-2
C:-3
D:-4
Ans: D
18:-A sinusoidal voltage of amplitude 1 kV is amplitude modulated by another sinusoidal voltage to produce 30% modulation. The amplitude of each sideband term is
A:-300 volts
B:-150 volts
C:-500 volts
D:-250 volts
Ans: B
19:-An interrupt in which the external device supplies its address as well as the interrupt request is known as
A:-Vectored interrupt
B:-Maskable interrupt
C:-Non - Maskable interrupt
D:-Designated interrupt
Ans: A
20:-Logic 1 in negative logic system is represented by
A:-Zero level
B:-Lower voltage level
C:-Higher voltage level
D:-Negative voltage
Ans: B
21:-A free electron means?
A:-All the electrons in an atom.
B:-The electrons not belongs to the atom itself.
C:-Valance electrons which are loosely attached to the nucleous.
D:-All the above
Ans: C
22:-The speed with which the effect of emf is experienced at all parts of a conductor resulting the flow of current is
A:-Velocity of charge
B:-Velocity of propagation of electric field
C:-Speed of response
D:-None of above
Ans: B
23:-When a potential difference is applied to a resistor the heat is produced by
A:-Due to the collision of free electrons with the molecules or atoms of the resistor
B:-Power dissipation
C:-Speed of response
D:-None of above
Ans: A
24:-On application of heat on electrolyte it exhibit
A:-Positive temp. coefficient
B:-No change in its resistance
C:-Resistance will increase
D:-Negative temp. Coefficient.
Ans: D
25:-An operational amplifier is a
A:-dependent source
B:-Independent source
C:-model source
D:-None of above
Ans: A
26:-A wire of resistance of 6 ohms is bent in the form of a circle , the effective resistance between two points on
any diameter is
A:-6 ohm
B:-12 ohm
C:-1.5 ohm
D:-9 ohm
Ans: C
27:-A wire of resistance R ohm is streatched to double its length, then its resistance become
A:-R/4
B:-R/2
C:-2R
D:-4R
Ans: D
28:-Two parallel wires carrying current in opposite direction
A:-Attracts each other
B:-Repel each other
C:-cancel each other
D:-None of the above
Ans: B
29:-A coil has a resistance of 25 ohm and inductance of 5H is connected to a DC source of 50V is suddenly switched off what will be the value of current at the time of switching off
A:-2A
B:-10A
C:-1.96A
D:-0.5A
Ans: A
30:-The inductive reactance of an inductor in a DC circuit is
A:-2∏fL
B:-Zero
C:-ωL
D:-∞
Ans: B
31:-In a circuit element if the p.d is higher than the applied voltage of the source then it will be
A:-DC circuit
B:-Neither ac nor dc circuit
C:-AC circuit
D:-For both circuit
Ans: C
32:-The moving system of an indicating type of electrical instrument is subjected to
A:-A deflecting torque
B:-Controlling torque
C:-Damping torque
D:-All the above
Ans: D
33:-The most efficient damping employed in electrical instrument is
A:-Air friction
B:-Fluid friction
C:-Eddy current
D:-None of the above
Ans: C
34:-In thermocouple ammeter the heat produced is proportional to
A:-Current
B:-Square root of current
C:-square of current
D:-voltage
Ans: C
35:-In a cross coil megger ,when two currents are passing through them The torque acting up on the coil
A:-opposite direction
B:-same direction
C:-TanΦ
D:-none of the above
Ans: A
36:-The frequency error in induction type ammeter is compensated by
A:-Self compensated
B:-not required
C:-non inductive shunt
D:-inductive shunt
Ans: C
37:-An induction watt meter consist of
A:-series electromagnet
B:-shunt electromagnet
C:-permanent magnet
D:-series and shunt electromagnet
Ans: D
38:-The efficiency of a solar cell is
A:-High
B:-Very high
C:-Low
D:-Very low
Ans: C
39:-in core type transformers the number of flux paths are
A:-2
B:-more than 2
C:-Half of the path
D:-single
Ans: D
40:-The relation between the excitation current and magnetic flux of a transformer is
A:-Current leads flux
B:-Flux leads the current
C:-They are in phase
D:-None of the above
Ans: A
41:-The equivalent resistance and leakage reactance of a transformer can be found out by
A:-Open circuit test
B:-short circuit test
C:-polarity test
D:-None of the above
Ans: B
42:-Hydro generator is the commercial name of
A:-Round rotor generator
B:-Cylindrical rotor synchronous generator
C:-Salient pole synchronous generator
D:-All the above
Ans: C
43:-An electrical machine with lower efficiency will have
A:-Less losses
B:-More losses
C:-No losses
D:-Low operating cost
Ans: B
44:-The effect of armature reaction under the pole shoes can be limited by
A:-Inter poles
B:-High reluctance pole tips
C:-Compensating windings
D:-All the above
Ans: C
45:-DC motors are started by using starters because
A:-To increase the starting current
B:-To reduce the staring current
C:-To increase the speed
D:-none of the above
Ans: B
46:-Swinburne 's test can not be performed on
A:-Shunt motor
B:-compound motor
C:-series motor
D:-All the above
Ans: C
47:-which of the following are used as constant speed drive
A:-Dc shunt motor
B:-DC series motor
C:-DC compound motor
D:-All the above
Ans: A
48:-No load slip of an induction motor is
A:-Large
B:-No slip
C:-Very small
D:-None of the above
Ans: C
49:-The relative advantage of a cage motor over a wound rotor motor of same power is
A:-Cage motor is More efficient
B:-Cage motor is less cost
C:-Better operating power factor
D:-All the above
Ans: D
50:-The maximum torque of an induction motor is proportional to
A:-Square of supply voltage
B:-Supply voltage
C:-Reciprocal of the square of supply voltage
D:-None of the above
Ans: A
51:-A synchronous motor runs on
A:-AC only
B:-DC only
C:-Both ac and dc
D:-None of the above
Ans: A
52:-If the armature coil of a DC machine is N turns then Number of conductors of any coil side
A:-2N
B:-N/2
C:-N²
D:-N
Ans: D
53:-The distance between two consecutive and similar top coil side is called
A:-Back pitch
B:-Front pitch
C:-Winding pitch
D:-Commutator pitch
Ans: C
54:-In lap wound machine the number of brushes used is equal to
A:-number of poles
B:-2
C:-number of turns
D:-number of commutator segments
Ans: A
55:-A mooving iron instrument can measure
A:-AC
B:-AC & DC
C:-DC
D:-Pulse
Ans: B
56:-The emf developed in any physical system act in such a direction to tend to
A:-Decrease co energy at constant mmf
B:-Decrease the co energy at constant flux
C:-Increase the co energy at constant mmf
D:-Increase the co energy at constant flux
Ans: C
57:-The factor to be considered while selecting the site of a hydel power plant
A:-Quantity of water available
B:-Head of water
C:-Accessibility of the site
D:-All the above
Ans: D
58:-Specific speed of a turbine is the speed at which it develop 1 metric HP under the head of
A:-1 metric meter
B:-1 meter
C:-1 feet
D:-1 cubic meter
Ans: B
59:-The active recovery voltage depends on
A:-Power factor
B:-Armature reaction
C:-Circuit condition
D:-All the above
Ans: D
60:-The highest current that a circuit breaker is capable of breaking at recovery and re striking voltage is
A:-Breaking capacity
B:-Making capacity
C:-Recovery current
D:-recovery voltage
Ans: A
61:-Circuit breaker intended for rapid auto re closing with rated operating duty o-m-co in which m represents
A:-Making
B:-Breaking
C:-Dead time
D:-Re closing
Ans: C
62:-The heat produced by an electric heating element is according to
A:-Ohm's law
B:-Stefan's law
C:-Snell's law
D:-Faraday's law
Ans: B
63:-Ajax Wyatt furnace make use of a crucible in
A:-Horizontal
B:-At an angle of 120°
C:-Vertical
D:-None of the above
Ans: C
64:-High frequency capacitance heating method is employed for heating
A:-Plastic
B:-Wood
C:-Dehydration of foods
D:-All the above
Ans: D
A:-All the electrons in an atom.
B:-The electrons not belongs to the atom itself.
C:-Valance electrons which are loosely attached to the nucleous.
D:-All the above
Ans: C
22:-The speed with which the effect of emf is experienced at all parts of a conductor resulting the flow of current is
A:-Velocity of charge
B:-Velocity of propagation of electric field
C:-Speed of response
D:-None of above
Ans: B
23:-When a potential difference is applied to a resistor the heat is produced by
A:-Due to the collision of free electrons with the molecules or atoms of the resistor
B:-Power dissipation
C:-Speed of response
D:-None of above
Ans: A
24:-On application of heat on electrolyte it exhibit
A:-Positive temp. coefficient
B:-No change in its resistance
C:-Resistance will increase
D:-Negative temp. Coefficient.
Ans: D
25:-An operational amplifier is a
A:-dependent source
B:-Independent source
C:-model source
D:-None of above
Ans: A
26:-A wire of resistance of 6 ohms is bent in the form of a circle , the effective resistance between two points on
any diameter is
A:-6 ohm
B:-12 ohm
C:-1.5 ohm
D:-9 ohm
Ans: C
27:-A wire of resistance R ohm is streatched to double its length, then its resistance become
A:-R/4
B:-R/2
C:-2R
D:-4R
Ans: D
28:-Two parallel wires carrying current in opposite direction
A:-Attracts each other
B:-Repel each other
C:-cancel each other
D:-None of the above
Ans: B
29:-A coil has a resistance of 25 ohm and inductance of 5H is connected to a DC source of 50V is suddenly switched off what will be the value of current at the time of switching off
A:-2A
B:-10A
C:-1.96A
D:-0.5A
Ans: A
30:-The inductive reactance of an inductor in a DC circuit is
A:-2∏fL
B:-Zero
C:-ωL
D:-∞
Ans: B
31:-In a circuit element if the p.d is higher than the applied voltage of the source then it will be
A:-DC circuit
B:-Neither ac nor dc circuit
C:-AC circuit
D:-For both circuit
Ans: C
32:-The moving system of an indicating type of electrical instrument is subjected to
A:-A deflecting torque
B:-Controlling torque
C:-Damping torque
D:-All the above
Ans: D
33:-The most efficient damping employed in electrical instrument is
A:-Air friction
B:-Fluid friction
C:-Eddy current
D:-None of the above
Ans: C
34:-In thermocouple ammeter the heat produced is proportional to
A:-Current
B:-Square root of current
C:-square of current
D:-voltage
Ans: C
35:-In a cross coil megger ,when two currents are passing through them The torque acting up on the coil
A:-opposite direction
B:-same direction
C:-TanΦ
D:-none of the above
Ans: A
36:-The frequency error in induction type ammeter is compensated by
A:-Self compensated
B:-not required
C:-non inductive shunt
D:-inductive shunt
Ans: C
37:-An induction watt meter consist of
A:-series electromagnet
B:-shunt electromagnet
C:-permanent magnet
D:-series and shunt electromagnet
Ans: D
38:-The efficiency of a solar cell is
A:-High
B:-Very high
C:-Low
D:-Very low
Ans: C
39:-in core type transformers the number of flux paths are
A:-2
B:-more than 2
C:-Half of the path
D:-single
Ans: D
40:-The relation between the excitation current and magnetic flux of a transformer is
A:-Current leads flux
B:-Flux leads the current
C:-They are in phase
D:-None of the above
Ans: A
41:-The equivalent resistance and leakage reactance of a transformer can be found out by
A:-Open circuit test
B:-short circuit test
C:-polarity test
D:-None of the above
Ans: B
42:-Hydro generator is the commercial name of
A:-Round rotor generator
B:-Cylindrical rotor synchronous generator
C:-Salient pole synchronous generator
D:-All the above
Ans: C
43:-An electrical machine with lower efficiency will have
A:-Less losses
B:-More losses
C:-No losses
D:-Low operating cost
Ans: B
44:-The effect of armature reaction under the pole shoes can be limited by
A:-Inter poles
B:-High reluctance pole tips
C:-Compensating windings
D:-All the above
Ans: C
45:-DC motors are started by using starters because
A:-To increase the starting current
B:-To reduce the staring current
C:-To increase the speed
D:-none of the above
Ans: B
46:-Swinburne 's test can not be performed on
A:-Shunt motor
B:-compound motor
C:-series motor
D:-All the above
Ans: C
47:-which of the following are used as constant speed drive
A:-Dc shunt motor
B:-DC series motor
C:-DC compound motor
D:-All the above
Ans: A
48:-No load slip of an induction motor is
A:-Large
B:-No slip
C:-Very small
D:-None of the above
Ans: C
49:-The relative advantage of a cage motor over a wound rotor motor of same power is
A:-Cage motor is More efficient
B:-Cage motor is less cost
C:-Better operating power factor
D:-All the above
Ans: D
50:-The maximum torque of an induction motor is proportional to
A:-Square of supply voltage
B:-Supply voltage
C:-Reciprocal of the square of supply voltage
D:-None of the above
Ans: A
51:-A synchronous motor runs on
A:-AC only
B:-DC only
C:-Both ac and dc
D:-None of the above
Ans: A
52:-If the armature coil of a DC machine is N turns then Number of conductors of any coil side
A:-2N
B:-N/2
C:-N²
D:-N
Ans: D
53:-The distance between two consecutive and similar top coil side is called
A:-Back pitch
B:-Front pitch
C:-Winding pitch
D:-Commutator pitch
Ans: C
54:-In lap wound machine the number of brushes used is equal to
A:-number of poles
B:-2
C:-number of turns
D:-number of commutator segments
Ans: A
55:-A mooving iron instrument can measure
A:-AC
B:-AC & DC
C:-DC
D:-Pulse
Ans: B
56:-The emf developed in any physical system act in such a direction to tend to
A:-Decrease co energy at constant mmf
B:-Decrease the co energy at constant flux
C:-Increase the co energy at constant mmf
D:-Increase the co energy at constant flux
Ans: C
57:-The factor to be considered while selecting the site of a hydel power plant
A:-Quantity of water available
B:-Head of water
C:-Accessibility of the site
D:-All the above
Ans: D
58:-Specific speed of a turbine is the speed at which it develop 1 metric HP under the head of
A:-1 metric meter
B:-1 meter
C:-1 feet
D:-1 cubic meter
Ans: B
59:-The active recovery voltage depends on
A:-Power factor
B:-Armature reaction
C:-Circuit condition
D:-All the above
Ans: D
60:-The highest current that a circuit breaker is capable of breaking at recovery and re striking voltage is
A:-Breaking capacity
B:-Making capacity
C:-Recovery current
D:-recovery voltage
Ans: A
61:-Circuit breaker intended for rapid auto re closing with rated operating duty o-m-co in which m represents
A:-Making
B:-Breaking
C:-Dead time
D:-Re closing
Ans: C
62:-The heat produced by an electric heating element is according to
A:-Ohm's law
B:-Stefan's law
C:-Snell's law
D:-Faraday's law
Ans: B
63:-Ajax Wyatt furnace make use of a crucible in
A:-Horizontal
B:-At an angle of 120°
C:-Vertical
D:-None of the above
Ans: C
64:-High frequency capacitance heating method is employed for heating
A:-Plastic
B:-Wood
C:-Dehydration of foods
D:-All the above
Ans: D
65:-in carbon arc welding the carbon electrode with respect to work is
A:-Negative
B:-Positive
C:-As positive or negative
D:-Non of the above
Ans: A
66:-The filament lamp work at a pf of
A:-.5
B:-1
C:-.7
D:-0
Ans: B
67:-Which lamp has the highest luminous efficiency
A:-Filament
B:-Neon
C:-Mercury vapor
D:-Sodium vapor
Ans: D
68:-In illumination space to height ratio is
A:-1 to 2
B:-1
C:-less than 1
D:-None of the above
Ans: A
69:-The induction motor cannot run at synchronous speed because if so
A:-Rotor emf would be zero
B:-Rotor current would be zero
C:-Rotor torque would be zero
D:-All the above
Ans: D
70:-Semi closed or totally closed slots are used in 3Ø Induction Motor essentially to
A:-Reduce magnetizing current
B:-Increase efficiency
C:-Improve starting torque
D:-Increase magnetizing current
Ans: A
71:-In DC machine the armature windings are placed on the rotor for effective
A:-Generation of voltage
B:-Development of torque
C:-Commutation
D:-Energy conversion
Ans: C
72:-The most powerful electromagnet in a normal DC machine operating at full load condition is
A:-Field winding
B:-Armature winding
C:-inter pole winding
D:-Compensating winding
Ans: A
73:-Which of the following is called as stray flux
A:-Armature flux
B:-Field flux
C:-Leakage flux
D:-None of the above
Ans: C
74:-When a coil moves through a time varying flux the induced emf present in the coil is
A:-Dynamically induced
B:-Statically induced
C:-Motional emf
D:-Both dynamically and Statically induced
Ans: D
75:-A 3 Ø SCIM stator rewound for 6 poles withh out any alteration in the rotor will run at a speed
A:-<1000 rpm
B:-<1500 rpm
C:-<1200 rpm
D:-0 rpm
Ans: A
76:-A 3Ø star connected IM takes 20A from supply. When connected in delta the motor will take a current of
A:-20√3 A
B:-20/√3 A
C:-20 A
D:-10A
Ans: A
77:-The armature core of a DC machine is laminated to minimise
A:-Hysteresis loss
B:-Eddy current loss
C:-Mechanical loss
D:-Temperature loss
Ans: B
78:-Which part of a DC motor has the maximum flux
A:-pole core
B:-Interpole
C:-Leading pole tip
D:-Trailing pole tip
Ans: C
79:-The air blast circuit breaker have best application in system of operating voltage
A:-Below 132KV
B:-132KV to 400KV
C:-Above 400KVA
D:-None of this
Ans: B
80:-The cheapest shielding material used in Nuclear plant is
A:-Concrete
B:-Brick
C:-Boron
D:-Cadmium
Ans: A
A:-Negative
B:-Positive
C:-As positive or negative
D:-Non of the above
Ans: A
66:-The filament lamp work at a pf of
A:-.5
B:-1
C:-.7
D:-0
Ans: B
67:-Which lamp has the highest luminous efficiency
A:-Filament
B:-Neon
C:-Mercury vapor
D:-Sodium vapor
Ans: D
68:-In illumination space to height ratio is
A:-1 to 2
B:-1
C:-less than 1
D:-None of the above
Ans: A
69:-The induction motor cannot run at synchronous speed because if so
A:-Rotor emf would be zero
B:-Rotor current would be zero
C:-Rotor torque would be zero
D:-All the above
Ans: D
70:-Semi closed or totally closed slots are used in 3Ø Induction Motor essentially to
A:-Reduce magnetizing current
B:-Increase efficiency
C:-Improve starting torque
D:-Increase magnetizing current
Ans: A
71:-In DC machine the armature windings are placed on the rotor for effective
A:-Generation of voltage
B:-Development of torque
C:-Commutation
D:-Energy conversion
Ans: C
72:-The most powerful electromagnet in a normal DC machine operating at full load condition is
A:-Field winding
B:-Armature winding
C:-inter pole winding
D:-Compensating winding
Ans: A
73:-Which of the following is called as stray flux
A:-Armature flux
B:-Field flux
C:-Leakage flux
D:-None of the above
Ans: C
74:-When a coil moves through a time varying flux the induced emf present in the coil is
A:-Dynamically induced
B:-Statically induced
C:-Motional emf
D:-Both dynamically and Statically induced
Ans: D
75:-A 3 Ø SCIM stator rewound for 6 poles withh out any alteration in the rotor will run at a speed
A:-<1000 rpm
B:-<1500 rpm
C:-<1200 rpm
D:-0 rpm
Ans: A
76:-A 3Ø star connected IM takes 20A from supply. When connected in delta the motor will take a current of
A:-20√3 A
B:-20/√3 A
C:-20 A
D:-10A
Ans: A
77:-The armature core of a DC machine is laminated to minimise
A:-Hysteresis loss
B:-Eddy current loss
C:-Mechanical loss
D:-Temperature loss
Ans: B
78:-Which part of a DC motor has the maximum flux
A:-pole core
B:-Interpole
C:-Leading pole tip
D:-Trailing pole tip
Ans: C
79:-The air blast circuit breaker have best application in system of operating voltage
A:-Below 132KV
B:-132KV to 400KV
C:-Above 400KVA
D:-None of this
Ans: B
80:-The cheapest shielding material used in Nuclear plant is
A:-Concrete
B:-Brick
C:-Boron
D:-Cadmium
Ans: A
81:-The Binary number system has a radix of :
A:-10
B:-2
C:-16
D:-8
Ans: B
82:-Class Y insulation temperature assigned __________ Range.
A:-105°C
B:-120°C
C:-90°C
D:-130°C
Ans: C
83:-In an Inductive load power factor :
A:-Zero
B:-Leading
C:-Lagging
D:-Both
Ans: C
84:-Form factor of an Electric Current :
A:-2
B:-1.11
C:-1.44
D:-1.732
Ans: B
85:-Intermediate switches are used to control :
A:-One lamp two places
B:-One lamp one place
C:-2 lamp one place
D:-More lamp from different places
Ans: D
86:-What is used for making guide holes drilling in metals ?
A:-Centre punch
B:-Ratchet Brace
C:-Auger-bit
D:-Hand Drill
Ans: A
87:-Upto how much voltage is medium ?
A:-Upto 250 V
B:-Upto 560 V
C:-Upto 11000 V
D:-Upto 440 V
Ans: B
88:-Nichrome is widely used for :
A:-Transformer winding
B:-Circuit connections
C:-Heater coils
D:-Lamp filaments
Ans: C
89:-The resistance of a conductor on increasing the temperature :
A:-Increases
B:-Decreases
C:-Constant
D:-Varies
Ans: A
90:-The unit for flux density is :
A:-Henry/`m^2` ` `
B:-Newton/`m^2`
C:-Webers/`m^2`
D:-None of the above
Ans: C
91:-The magnetic potential in a magnetic circuit can be measured in terms of :
A:-Farads
B:-Coulombs
C:-EMF
D:-MMF
Ans: D
92:-Which one of the following capacitors is only suitable for direct voltage ?
A:-Aluminium foil capacitor
B:-Metalic paper capacitor
C:-Unpoled aluminium elctrolyte capacitor
D:-Poled aluminium electrolyte capacitor
Ans: D
93:-Which resistor is commonly used for general purpose application ?
A:-Wire-wound resistors
B:-Carbon resistors
C:-Metal film resistors
D:-Carbon film resistors
Ans: B
94:-To solder resistors on a PCB the soldering iron wattage should be :
A:-25
B:-60
C:-150
D:-240
Ans: A
95:-Intermediate frequency transformers use :
A:-Iron core
B:-Ferrite core
C:-Air core
D:-Both Iron core and Air core
Ans: B
96:-In a DC circuit capacitor acts like a :
A:-Open Circuit
B:-Inductance
C:-Short Circuit
D:-Resistance whose value depends on the dielectic material
Ans: A
97:-Which one of them is not a semiconductor ?
A:-Silicon
B:-Germanium
C:-Carbon
D:-Galium arsenide
Ans: D
98:-The process of adding impurities to a pure semiconductors is known as :
A:-Diffusion
B:-Forming
C:-Doping
D:-Etching
Ans: C
99:-When a germanium diode is connected in forward biased mode the voltage across the diode will be :
A:-Zero
B:-0.7 Volt
C:-Equal to applied voltage
D:-0.3 Volt
Ans: D
100:-The function of a diode can be compared with a :
A:-Replay
B:-Switch
C:-Inductor
D:-Fuse
Ans: B
A:-10
B:-2
C:-16
D:-8
Ans: B
82:-Class Y insulation temperature assigned __________ Range.
A:-105°C
B:-120°C
C:-90°C
D:-130°C
Ans: C
83:-In an Inductive load power factor :
A:-Zero
B:-Leading
C:-Lagging
D:-Both
Ans: C
84:-Form factor of an Electric Current :
A:-2
B:-1.11
C:-1.44
D:-1.732
Ans: B
85:-Intermediate switches are used to control :
A:-One lamp two places
B:-One lamp one place
C:-2 lamp one place
D:-More lamp from different places
Ans: D
86:-What is used for making guide holes drilling in metals ?
A:-Centre punch
B:-Ratchet Brace
C:-Auger-bit
D:-Hand Drill
Ans: A
87:-Upto how much voltage is medium ?
A:-Upto 250 V
B:-Upto 560 V
C:-Upto 11000 V
D:-Upto 440 V
Ans: B
88:-Nichrome is widely used for :
A:-Transformer winding
B:-Circuit connections
C:-Heater coils
D:-Lamp filaments
Ans: C
89:-The resistance of a conductor on increasing the temperature :
A:-Increases
B:-Decreases
C:-Constant
D:-Varies
Ans: A
90:-The unit for flux density is :
A:-Henry/`m^2` ` `
B:-Newton/`m^2`
C:-Webers/`m^2`
D:-None of the above
Ans: C
91:-The magnetic potential in a magnetic circuit can be measured in terms of :
A:-Farads
B:-Coulombs
C:-EMF
D:-MMF
Ans: D
92:-Which one of the following capacitors is only suitable for direct voltage ?
A:-Aluminium foil capacitor
B:-Metalic paper capacitor
C:-Unpoled aluminium elctrolyte capacitor
D:-Poled aluminium electrolyte capacitor
Ans: D
93:-Which resistor is commonly used for general purpose application ?
A:-Wire-wound resistors
B:-Carbon resistors
C:-Metal film resistors
D:-Carbon film resistors
Ans: B
94:-To solder resistors on a PCB the soldering iron wattage should be :
A:-25
B:-60
C:-150
D:-240
Ans: A
95:-Intermediate frequency transformers use :
A:-Iron core
B:-Ferrite core
C:-Air core
D:-Both Iron core and Air core
Ans: B
96:-In a DC circuit capacitor acts like a :
A:-Open Circuit
B:-Inductance
C:-Short Circuit
D:-Resistance whose value depends on the dielectic material
Ans: A
97:-Which one of them is not a semiconductor ?
A:-Silicon
B:-Germanium
C:-Carbon
D:-Galium arsenide
Ans: D
98:-The process of adding impurities to a pure semiconductors is known as :
A:-Diffusion
B:-Forming
C:-Doping
D:-Etching
Ans: C
99:-When a germanium diode is connected in forward biased mode the voltage across the diode will be :
A:-Zero
B:-0.7 Volt
C:-Equal to applied voltage
D:-0.3 Volt
Ans: D
100:-The function of a diode can be compared with a :
A:-Replay
B:-Switch
C:-Inductor
D:-Fuse
Ans: B
1. If R = 40 Ω, L = 4 H and C = 1 /4 F. what type of natural response will the series RLC circuit has
Over damped
2. A three-phase motor can be regarded as a balanced Y-load. A three phase motor draws 5.6 kW when the line voltage is 220 V and the line current is 18.2 A. what is the power factor of the motor?
0.8075
3. A balanced delta-connected load is supplied by a 60-Hz three-phase source with a line voltage of 240 V. Each load phase draws 6 kW at a lagging power factor of 0.8. What is the value of capacitance needed to be connected in parallel with each load phase to minimize the current from the source
207.2 µF
4. The material of wires used for making resistance standards is usually
Manganin
5. A moving coil instrument gives a full scale deflection of 10 mA when the potential difference across its terminals is 100 mV. What is the shunt resistance for a full scale deflection corresponding to 100 A
0.001 Ω
6. The power flowing in a 3-phase, 3 wire balanced load system is measured by two wattmeter method. The reading of wattmeter A is 7500 W and of wattmeter B is -1500 W. what is the power factor of the system?
0.358
7. Damping which is used in the electrodynamometer type wattmeter is
Air friction damping
8. The deflection of an electron beam on a CRT screen is 10 mm. suppose the pre-accelerating anode voltage is halved and the potential between deflecting plates is doubled, the deflection of the electron beam will be
40 mm
9. The bandwidth of a CRO is from 0-20 MHz. The fastest rise time a sine wave can have to be accurately reproduced by the instrument is 17.5 ns
10. Murray loop test is performed on a faulty cable 300 m long. At balance, the resistance connected to the faulty core was set at 15 Ω and the resistance of the resistor connected to the sound core was 45 Ω. What is the distance of the fault point from the test end in metres
150
11. Loop tests work on the principle of
Wheatstone bridge
12. One Foot-Candle is equivalent to
10.76 lux
13. A 60 W lamp given a luminous flux of 1500 lumen. Its efficiency is
25 lumen/watt
14. The distances of the screen from the lamp under test and standard lamp when adjusted are 1.6 m and 0.9 m respectively. If the standard lamp be of 80 CP, then what is the CP of the lamp under test
252.84 CP
15. The illumination at various points on a horizontal surface illuminated by the same source varies as
Cos3 Ѳ
Over damped
2. A three-phase motor can be regarded as a balanced Y-load. A three phase motor draws 5.6 kW when the line voltage is 220 V and the line current is 18.2 A. what is the power factor of the motor?
0.8075
3. A balanced delta-connected load is supplied by a 60-Hz three-phase source with a line voltage of 240 V. Each load phase draws 6 kW at a lagging power factor of 0.8. What is the value of capacitance needed to be connected in parallel with each load phase to minimize the current from the source
207.2 µF
4. The material of wires used for making resistance standards is usually
Manganin
5. A moving coil instrument gives a full scale deflection of 10 mA when the potential difference across its terminals is 100 mV. What is the shunt resistance for a full scale deflection corresponding to 100 A
0.001 Ω
6. The power flowing in a 3-phase, 3 wire balanced load system is measured by two wattmeter method. The reading of wattmeter A is 7500 W and of wattmeter B is -1500 W. what is the power factor of the system?
0.358
7. Damping which is used in the electrodynamometer type wattmeter is
Air friction damping
8. The deflection of an electron beam on a CRT screen is 10 mm. suppose the pre-accelerating anode voltage is halved and the potential between deflecting plates is doubled, the deflection of the electron beam will be
40 mm
9. The bandwidth of a CRO is from 0-20 MHz. The fastest rise time a sine wave can have to be accurately reproduced by the instrument is 17.5 ns
10. Murray loop test is performed on a faulty cable 300 m long. At balance, the resistance connected to the faulty core was set at 15 Ω and the resistance of the resistor connected to the sound core was 45 Ω. What is the distance of the fault point from the test end in metres
150
11. Loop tests work on the principle of
Wheatstone bridge
12. One Foot-Candle is equivalent to
10.76 lux
13. A 60 W lamp given a luminous flux of 1500 lumen. Its efficiency is
25 lumen/watt
14. The distances of the screen from the lamp under test and standard lamp when adjusted are 1.6 m and 0.9 m respectively. If the standard lamp be of 80 CP, then what is the CP of the lamp under test
252.84 CP
15. The illumination at various points on a horizontal surface illuminated by the same source varies as
Cos3 Ѳ
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