1.
The energy stored in a capacitor as a function of voltage (V) is given by
A
CV^{2}
B
CV^{2<}
C
D
None of these
Answer/ Hint
Answer :
B
Explanation :
Energy stored in a capacitor = QV CV.V [ Q = CV] = CV^{2}
Where, Q = change stored in capacitor plate
V = developed voltage across capacitor plate
C = capacitor of the capacitor
2.
A 100Ω, 1 watt resistor can sustain a maximum current of
A
100 mA
B
10A
C
1A
D
None of these
Answer/ Hint
Answer :
A
Explanation :
P = I^{2} R
3.
If all the three resistances of a given Delta network are 15Ω each, then all the three resistances of the equivalent star will be
A
45 Ω each
B
30 Ω each
C
5 Ω each
D
15 Ω each
Answer/ Hint
Answer :
C
Explanation :
Equivalent star resistance of each phase =
4.
If all the three resistances of a given star network are 10 each, then all the three resistances of the equivalent delta network
A
Will be 30 Ω each
B
Will be 3.33 Ω each
C
Will not be all equal
D
Will be 20 Ω each
Answer/ Hint
Answer :
A
Explanation :
Equivalent delta resistance of each phase =
Where, R_{1} , R_{2} and R_{3} all are three star resistances and R_{1} = R_{2} = R_{3} = 10 Ω
Equivalent delta resistance = = 30 Ω
5.
An electrical network with seven independent branches and five independent nodes excluding the reference node should preferably be solved by
A
Mesh current analysis
B
Node voltage analysis
C
Kirchoff’s current law
D
None of these
Answer/ Hint
Answer :
A
Explanation :
For mesh current analysis, no. of independent mesh or loop equations m are
m = b – n + 1
Where, b = no. of branches
n = no. of nodes
m = 7 -5 + 1 = 3
6.
Most commonly employed trivalent impurities are
A
Boron, indium
B
Arsenic, antimony
C
Boron, arsenic
D
Indium, antimony
Answer/ Hint
Answer :
A
Explanation :
Trivalent impurity (such as Boron, indium) has three valance electrons in their outermost shell, it is also known as p-type impurities in the case of transistor action.
7.
Most commonly employed pentavalent impurities are
A
Boron, indium
B
Aluminium , antimony
C
Arsenic , indium
D
Arsenic , antimony
Answer/ Hint
Answer :
D
Explanation :
pentavalent impurity (such as Arsenic, Antimony) has five valance electrons in their outermost shell, it releases electrons into the material in which it is added so it is also known as n-type impurities in the transistor action
8.
An N-type semiconductor as a whole is
A
Electrically neutral
B
Positively charged
C
Negatively charged
D
None of these
Answer/ Hint
Answer :
A
Explanation :
An n-type semiconductor as a whole is ordinary metal like copper so it is basically electrically neutral as a whole material in which conduction takes place by application of potential difference
9.
Which of the following is the dimensional formula for conductivity
A
M^{- 1} L^{- 3} T^{3} A^{2} .
B
ML^{3} T^{-3} A^{-2} .
C
M^{2} L^{2} T^{-3} A^{-2} .
D
ML^{2} T^{3} A^{-2} .
Answer/ Hint
10.
Which of the following is the CORRECT expression for the capacitance of a parallel plate capacitor
A
B
C
D
Answer/ Hint
11.
In a series combination of several inductors, the equivalent inductance is ________ .
A
Equal to the largest inductance of the combination.
B
Lower than the largest inductance of the combination.
C
Lower than the smallest inductance of the combination.
D
Greater than the largest inductance of the combination.
Answer/ Hint
12.
Which of the following is the reciprocal of resistivity
A
Reluctivity
B
Susceptibility
C
Conductivity
D
Permittivity
Answer/ Hint
13.
Determine the value of equivalent inductance, if 4 inductors having inductance L are connected in parallel
A
4L
B
L/4
C
4/L
D
8L
Answer/ Hint
14.
Determine the conductance (in Siemens) of a conductor, when the potential difference between the ends of the conductor is 30 V and the current flowing through the conductor is 3A
A
0.1
B
1.1
C
2.4
D
4.2
Answer/ Hint
15.
How much power (in W) will be dissipated by a 10 ohms resistor, when the current through the resistor is 3 A
A
30
B
40
C
60
D
90
Answer/ Hint
16.
Determine the value of resistance (in ohms) of a resistor at 40 degree Celsius, when the resistance has a resistance of 10 Ohms at 0 degree Celsius and the temperature coefficient at 0 degree Celsius is 0.04
A
20
B
23
C
24
D
26
Answer/ Hint
17.
Determine the energy stored (in J) by a 5 H inductor, when the current flowing through the inductor is 6 A>
A
94
B
90
C
60
D
40
Answer/ Hint
18.
Determine the equivalent resistance (in Ohms) for the circuit given below Figure
A
2
B
4
C
6
D
9
Answer/ Hint
19.
Determine the resistance (in Ohms) of resistor when the potential difference between the ends of the resistor is 24 V and the current flowing through the resistor is 3 A
A
12
B
10
C
8
D
4
Answer/ Hint
20.
Determine the value of current I_{3} (in A) for the diagram given below Figure
A
1
B
2
C
3
D
4
Answer/ Hint
21.
Which of the following statement is TRUE
A
The current always flows in the direction of flow of electrons.
B
The current always flows opposite to the direction of flow of electrons.
C
The current always flows from negative terminal to positive terminal.
D
The electrons always flows from positive terminal to negative terminal.
Answer/ Hint
22.
Determine the Norton’s resistance (in Ohms) between terminal A and B for the circuit given below Figure
A
6.5
B
5.4
C
4.5
D
3.5
Answer/ Hint
23.
Determine the value of current I (in A) drawn from the voltage source for the circuit given below Figure
A
2.5
B
3.4
C
4.3
D
6.5
Answer/ Hint
24.
Determine the value of source resistance (in Ohms) for transmitting maximum power from the source to the load, when the load impedance of the circuit is 10 – j2 Ohms
A
2
B
10
C
-2
D
-10
Answer/ Hint
25.
Determine the power (in W) delivered from the source for the circuit given below Figure
A
23.8
B
26.6
C
24.6
D
22.6
Answer/ Hint
26.
Determine the value of Thevenin’s equivalent resistance (in Ohms) across terminal A and B for the electrical circuit given below Figure
A
1
B
2
C
6
D
8
Answer/ Hint
27.
Determine the value of load resistance (in ohms) for a circuit, when the maximum power transferred from the source of 50 V to the load is 25 W
A
50
B
40
C
35
D
25
Answer/ Hint
28.
What will happen to the inductance, if number of turns of the coil is decreased
A
Increase
B
Decreases
C
Remain same
D
None of these
Answer/ Hint
29.
If the area of cross-section is reduced to half of its original value, then what will happen to the flux density
A
Doubled
B
Halved
C
Remain same
D
One-fourth
Answer/ Hint
30.
Calculate the value of flux leakage coefficient, if 𝛷_{g} is the air gap flux and 𝛷_{a} is the flux in iron core
A
𝛷_{g} / 𝛷_{a}
B
𝛷_{a} / 𝛷_{g}
C
𝛷_{a} × 𝛷_{g}
D
𝛷_{a} + 𝛷_{g}
Answer/ Hint
31.
The graph shown represents the B-H curve for ________ Figure
A
Glass
B
Steel
C
Iron
D
Air
Answer/ Hint
32.
A conductor of length 0.6 m is situated at the right angle to a uniform magnetic field of flux density 4 Wb/sq. m. The conductor is moving with a velocity of 50 m/s. calculate the emf induced (in V) n the conductor
A
100
B
115
C
118
D
120
Answer/ Hint
33.
A 600-turn coil has a resistance of 7 ohms and an inductance of 0.8 H. if one-fifith of the turns are removed, then determine the new inductance (in H).
A
0.512
B
0.25
C
2
D
2.5
Answer/ Hint
34.
A magnetic circuit of reluctance 3000 A-turns/Wb is wounded by a wire of 400 turns. Determine the average emf induced (in V) in the coil, if a current of 2 A is flowing in the coil is reversed in 15 s
A
14.24
B
16.28
C
17.96
D
19.62
Answer/ Hint
35.
For the figure shown below, the permeability in the core is 4 × 10^{- 4} Wb/A-turns-m. what is the value of flux density (in T) in the core Figure
A
0.2
B
0.382
C
0.6
D
1
Answer/ Hint
36.
Which of the following represents the quality factor of a series RLC circuit
A
B
C
D
Answer/ Hint
37.
Which of the following represents the relation between the peak value and RMS value of voltage for a sine wave
A
B
C
D
Answer/ Hint
38.
Determine the average value of an alternating current (in A) when the peak value of the current is 10 A
A
14.14
B
10.63
C
6.37
D
4.36
Answer/ Hint
39.
What will be the frequency (in Hz) of a sinusoidal waveform, when the time period of the wave is 25 ms
A
40
B
50
C
60
D
80
Answer/ Hint
40.
Determine the total impedance (in ohms) of a series RLC circuit having a resistance of 10 Ohms, capacitive reactance of 2 ohms and inductive reactance of 6 ohms, connected in a series across a 200 V, 50 Hz supply
A
8.64
B
10.77
C
12.21
D
14.65
Answer/ Hint
41.
Determine the value of phase current (in A) for a balanced delta connected system, when the value of line current is 8.7 A.
A
8
B
7
C
6
D
5
Answer/ Hint
42.
What will be the value of inductance (in mH) connected in parallel with a capacitance of 4 F in a series RLC circuit having a quality factor 2, when the resonant frequency is 6 rad/sec
A
2
B
3
C
5
D
7
Answer/ Hint
43.
What will be the value of average power (in W), if a sinusoidal voltage applied across a series RC circuit is 20 sin V and the current flowing in the circuit is 10sin ( + 60) A
A
50
B
60
C
80
D
100
Answer/ Hint
44.
Determine the total power (in kW) consumed by a 3-phase delta connected system supplied by a line voltage of 230 V, if the value of phase current is 30 A and the current lags the voltage by 30 degree.
A
14.62
B
15.26
C
16.62
D
17.93
Answer/ Hint
45.
Which of the following bridge is most suitable for the measurement of an unknown resistance
A
Hay’s Bridge
B
Anderson Bridge
C
Wien’s Bridge
D
Wheatstone Bridge
Answer/ Hint
46.
Which of the following instrument is used for the measurement of Insulation resistance
A
Megger
B
Wattmeter
C
Ammeter
D
Voltmeter
Answer/ Hint
47.
What will be the deflection (in rad) of a moving iron instrument, when the inductance of the moving iron instrument is (20 +4θ) μH, where θ is the deflection in redian from zero position and the deflection current is 5 A ? Assuming spring constant k = 10 × 10^{- 6} Nm/rad
A
5
B
10
C
15
D
20
Answer/ Hint
48.
Determine the value of the unknown capacitance C_{x} (in μF) for the circuit given below, when no current flows through the detector (D) Figure
A
20
B
40
C
60
D
80
Answer/ Hint
49.
Which of the given losses are directly proportional to square of speed
A
Windage loss
B
Eddy current loss
C
Both windage and eddy current loss
D
Hysteresis loss and brush loss
Answer/ Hint
50.
Breather is provided in a transformer to
A
Absorb moisture of air during breathing
B
Provide cold air in transformer
C
Absorb moisture from air entering in transformer
D
Filter the transformer ail.
Answer/ Hint
51.
Armature reaction effect is more in
A
Field weakening method
B
Armature resistance control
C
Same in both methods
D
All option are correct
Answer/ Hint
52.
A shunt generator running at 1000 rpm generated emf of 100 V. If the speed increase to 1200 rpm, the generated emf is
A
140 V
B
120 V
C
240 V
D
360 V
Answer/ Hint
53.
The primary and secondary windings of a transformer are
A
Conductively linked
B
Inductively linked
C
Electrically linked
D
Mechanically linked
Answer/ Hint
54.
Which of the following is not a part of transformer
A
Commutator
B
Conservator tank
C
Radiator
D
Tap changer
Answer/ Hint
55.
Find the number of poles required, if the frequency is 50 Hz and speed of the motor is 500 rpm.
A
24 poles
B
12 poles
C
5 poles
D
10 poles
Answer/ Hint
56.
In squirrel cage induction, the rotor slots are slight skew in order to reduce
A
Windage losses
B
Eddy currents
C
Reduce magnetic humming effect
D
Friction losses
Answer/ Hint
57.
What type of operate a direct-on-line starter consists of a coil operated
A
Capacitor operated
B
A coil operated
C
Resistor operated
D
Eddy current operated
Answer/ Hint
58.
For a single phase capacitor start induction motor which of the following statements is valid
A
The capacitor is used for power factor improvement
B
The direction of rotation can be changed by reversing the main winding terminals
C
The direction of rotation cannot be changed
D
The direction of rotation can be changed by interchanging the supply terminals
Answer/ Hint
59.
The capacity of single phase induction motor is limited by
A
Pulsating torque
B
Uniform torque
C
Non uniform torque
D
None of these
Answer/ Hint
60.
The function of measurement system is/are ________
A
Indicating function
B
Recording function
C
Controlling function
D
Indicating, recording and controlling function
Answer/ Hint
61.
Which of the following motor will give relatively high starting torque
A
Capacitor end motor
B
Capacitor start motor
C
Split phase motor
D
Split motor
Answer/ Hint
62.
Transmission lines
A
Absorb reactive power when fully loaded and generate reactive power on light loads
B
Generate reactive power when fully loaded and absorb reactive power on light loads
C
Generate reactive power on light loads as well as fully loaded
D
Absorb reactive power on light loads as well as fully loaded
Answer/ Hint
63.
Maximum permissible span (in metre) for wooden poles is
A
10
B
20
C
30
D
75
Answer/ Hint
64.
A cable has an insulation of relative permittivity 2. If the insulation is replaced by one of relative permittivity 4, the capacitance of the cable will become
A
One fourth
B
Half
C
Double
D
Four times
Answer/ Hint
65.
Which insulator is used on dead ends of medium voltage line
A
Shackle type
B
Pin type
C
Egg type
D
Disc type
Answer/ Hint
66.
Which type of fire extinguisher is to be used on electrical equipment or installation under fire
A
Foam type
B
Halon type
C
Gas cartridge water filled type
D
Stored pressure water filled type
Answer/ Hint
67.
What is the unit of luminance
A
Candela
B
Lux
C
Candela / m^{2}
D
M^{2} / candela
Answer/ Hint
68.
Determine the power factor of 230V, 0.5 A, 40 W fluorescent lamp
A
0.348
B
0.438
C
0.843
D
0.4038
Answer/ Hint
69.
Which type of circuit breaker having higher rating
A
Miniature circuit breaker
B
Oil circuit breaker
C
Air circuit breaker
D
Vacuum circuit breaker
Answer/ Hint
70.
The function of the commutator in a DC machine is _________ .
A
To change alternating current into direct current
B
To improve commutation
C
For easy speed control
D
To change alternating voltage to direct voltage
Answer/ Hint
71.
The voltage level of the single phase supply to residential consumer is
A
220 V
B
210 V
C
230 V
D
240 V
Answer/ Hint
72.
A pin type insulator is made from
A
Porcelain
B
Glass
C
Plastic
D
All option are correct
Answer/ Hint
73.
How will you test the supply in plug point
A
Tester
B
Multi-meter
C
Voltmeter
D
All option are correct
Answer/ Hint
74.
Power factor correction substations consists of
A
Rectifiers
B
Inverters
C
Synchronous condenser
D
Transformers
Answer/ Hint
75.
Energy efficient motors generally have
A
Longer insulation
B
Less vibration
C
Lower heat output
D
All option are correct
Answer/ Hint
76.
Material used for making knife switch is
A
Nickel
B
Aluminium
C
Brass
D
Nichrome
Answer/ Hint
77.
Luminous efficiency of a fluorescent tube is
A
5 – 10 lumen / watt
B
15 – 20 lumen / watt
C
30 – 40 lumen / watt
D
60 – 65 lumen / watt
Answer/ Hint
78.
A fluorescent tube can be operated on
A
AC only
B
DC only
C
Both AC as well as DC
D
None of these
Answer/ Hint
79.
Induction heating process is based on which of the following principles
A
Thermal ion release principle
B
Nucleate heating principle
C
Resistance heating principle
D
Electromagnetic induction principle
Answer/ Hint
80.
A perfect black body is one which
A
Absorbs all incident radiations
B
Reflects all incident radiations
C
Transmits all incident radiations
D
All option are correct
Answer/ Hint
81.
Low frequency supply is obtained by
A
Motor-generator set
B
Frequency changer
C
Either Motor-generator set or Frequency changer
D
Both Motor-generator set or Frequency changer
Answer/ Hint
82.
A lamp of 500 watts having Mean spherical candle power (MSCP) of 1000 is suspended 2.7 metres above the working plane. Calculate illumination directly below the lamp at the working plane
A
100.87 lux
B
143.83 lux
C
137.17 lux
D
125.63 lux
Answer/ Hint
83.
The impurity added to extrinsic semiconductor is of the order of
A
1 in 10
B
1 in 1000
C
1 in million
D
1 in billion
Answer/ Hint
84.
Figure represents a Figure
A
Zener diode
B
Silicon controlled rectifier
C
Tunnel diode
D
Junction field effect transistor
Answer/ Hint
85.
In case of full wave rectifier, the ripple factor is
A
1.21
B
0.5
C
0.48
D
1
Answer/ Hint
86.
An amplifier is used to obtain
A
An increased voltage, current or power of an input signal
B
Alternation of the input signal
C
An amplification of frequency response of a communication signal
D
A distortion less reproduction of radio signals
Answer/ Hint
87.
The function of the emitter bypass capacitor in CE amplifier is
A
Provide a low resistance path for the AC signals
B
Provide a high resistance path for the AC signals
C
Act a low resistance path for the AC signals
D
Provide short circuit path for the DC signal
Answer/ Hint
88.
Synchronizing power of a synchronous machine is
A
Directly proportional to be synchronous reactance
B
Equal to the synchronous reactance
C
Inversely proportional to be synchronous reactance
D
None of these
Answer/ Hint
89.
The normal starting methods that is used to start a synchronous motor is
A
Star-delta starter
B
Damper winding
C
Resistance starter in the armature circuit
D
Damper winding in conjunction with star-delta starter
Answer/ Hint
90.
At what condition synchronous motor can be used as a synchronous capacitor
A
Under-loaded
B
Under-excited
C
Over-loaded
D
Over-excited
Answer/ Hint
91.
Synchronous motor do not have self-starting property because
A
Starting winding is not provided on the machines
B
The direction of rotations is not fixed
C
The direction of instantaneous torque reverses after half cycle
D
Starters cannot be used on these machines
Answer/ Hint
92.
The over-excited synchronous motor takes
A
Leading current
B
Lagging current
C
Both Leading current and Lagging current
D
None of these
Answer/ Hint
93.
A three-phase synchronous motor will have
A
One slip-ring
B
Two slip-ring
C
No slip-ring
D
Three slip-ring
Answer/ Hint