Official Paper

SSC JE CBT-II (Electrical Engineering) Official Paper (Held On 07 Apr, 2026) (Previous Year Paper)

100 questions · 120 minutes · with answers · free

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General Engineering (100 questions)

1

The armature reaction in a synchronous generator primarily serves which purpose?

  1. ((a))

    Improve voltage regulation

  2. ((b))

    Distort the main magnetic field

  3. ((c))

    Increase efficiency

  4. ((d))

    Reduce copper losses

Show Answer
Answer: ((a))

Improve voltage regulation

2

If the frequency of the incoming generator is higher than that of the bus bar, the synchroscope rotates in which direction?

  1. ((a))

    Clockwise

  2. ((b))

    Anticlockwise

  3. ((c))

    Stays stationary

  4. ((d))

    Vibrates

Show Answer
Answer: ((a))

Clockwise

3

For achieving linear amplification, a BJT must operate in which region?

  1. ((a))

    Cut-off region

  2. ((b))

    Saturation region

  3. ((c))

    Active region

  4. ((d))

    Reverse active region

Show Answer
Answer: ((a))

Cut-off region

4

What is the phase difference between the input and output signals in a common-emitter (CE) amplifier?

  1. ((a))

    0°

  2. ((b))

    90°

  3. ((c))

    180°

  4. ((d))

    360°

Show Answer
Answer: ((a))

0°

5

For sustained oscillations in an oscillator circuit, the loop gain must be:

  1. ((a))

    Less than unity

  2. ((b))

    Greater than unity

  3. ((c))

    Exactly unity with zero phase shift

  4. ((d))

    Zero

Show Answer
Answer: ((a))

Less than unity

6

The high power gain of a CE amplifier is mainly due to:

  1. ((a))

    High current gain

  2. ((b))

    High voltage gain

  3. ((c))

    Both A and B

  4. ((d))

    Low losses

Show Answer
Answer: ((a))

High current gain

7

A MOSFET functions as an amplifier when it operates in which region?

  1. ((a))

    Cut-off

  2. ((b))

    Triode

  3. ((c))

    Saturation

  4. ((d))

    Breakdown

Show Answer
Answer: ((a))

Cut-off

8

Differential protection is primarily used for the protection of which equipment?

  1. ((a))

    Transmission lines

  2. ((b))

    Feeders

  3. ((c))

    Generators and transformers

  4. ((d))

    Motors only

Show Answer
Answer: ((a))

Transmission lines

9

A circuit breaker rated for a short-circuit current of 25 kA indicates which capability of the breaker?

  1. ((a))

    Normal current

  2. ((b))

    Peak current

  3. ((c))

    Fault interrupting capacity

  4. ((d))

    Load current

Show Answer
Answer: ((a))

Normal current

10

A transformer protected by a Buchholz relay must be of which type?

  1. ((a))

    Air-cooled

  2. ((b))

    Oil-immersed

  3. ((c))

    Dry-type

  4. ((d))

    Gas-filled

Show Answer
Answer: ((a))

Air-cooled

11

SF6 SF_{6} circuit breakers are preferred mainly due to which advantage?

  1. ((a))

    Low cost

  2. ((b))

    High arc-quenching ability

  3. ((c))

    Simple construction

  4. ((d))

    High maintenance

Show Answer
Answer: ((a))

Low cost

12

A coaxial cable exhibits high transmission efficiency under which condition?

  1. ((a))

    Dielectric loss is maximum

  2. ((b))

    Conductor resistance is high

  3. ((c))

    Attenuation is minimum

  4. ((d))

    Operating frequency is zero

Show Answer
Answer: ((a))

Dielectric loss is maximum

13

Which wiring system is considered most suitable for use in damp or wet locations?

  1. ((a))

    Cleat wiring

  2. ((b))

    Batten wiring

  3. ((c))

    Casing and capping

  4. ((d))

    Conduit wiring

Show Answer
Answer: ((a))

Cleat wiring

14

Earth resistance decreases under which condition?

  1. ((a))

    Soil resistivity increases

  2. ((b))

    Moisture content increases

  3. ((c))

    Electrode length decreases

  4. ((d))

    Contact area reduces

Show Answer
Answer: ((a))

Soil resistivity increases

15

Which wiring system involves the highest initial cost but requires the least maintenance?

  1. ((a))

    Cleat wiring

  2. ((b))

    Batten wiring

  3. ((c))

    Casing and capping

  4. ((d))

    Conduit wiring

Show Answer
Answer: ((a))

Cleat wiring

16

The demand factor of an electrical installation is always which of the following?

  1. ((a))

    Equal to unity

  2. ((b))

    Less than unity

  3. ((c))

    Greater than unity

  4. ((d))

    Zero

Show Answer
Answer: ((a))

Equal to unity

17

Which equipment is most commonly used in industries for improving power factor?

  1. ((a))

    Inductor

  2. ((b))

    Capacitor bank

  3. ((c))

    Reactor

  4. ((d))

    Fuse

Show Answer
Answer: ((a))

Inductor

18

A load consumes 50 kW at a lagging power factor of 0.8. Determine the apparent power drawn by the load.

  1. ((a))

    40 kVA

  2. ((b))

    50 kVA

  3. ((c))

    62.5 kVA

  4. ((d))

    80 kVA

Show Answer
Answer: ((a))

40 kVA

19

For a constant kW load, a consumer improves the power factor from 0.8 to 0.95. What happens to the line current?

  1. ((a))

    Increase

  2. ((b))

    Decrease

  3. ((c))

    Remain constant

  4. ((d))

    First increases then decreases

Show Answer
Answer: ((a))

Increase

20

A transmission line supplies 50 MW of power at a power factor of 0.8. Calculate the reactive power supplied.

  1. ((a))

    30 MVAR

  2. ((b))

    37.5 MVAR

  3. ((c))

    50 MVAR

  4. ((d))

    62.5 MVAR

Show Answer
Answer: ((a))

30 MVAR

21

A load rated at 100 kVA operates at a power factor of 0.6. After power factor correction, it becomes 0.9. Find the reduction in kVA demand.

  1. ((a))

    20 kVA

  2. ((b))

    30 kVA

  3. ((c))

    33.3 kVA

  4. ((d))

    40 kVA

Show Answer
Answer: ((a))

20 kVA

22

The economic power factor of an industrial electrical system is defined as which value?

  1. ((a))

    Unity

  2. ((b))

    Zero

  3. ((c))

    Leading

  4. ((d))

    Slightly less than unity

Show Answer
Answer: ((a))

Unity

23

A transmission line has a resistance of 20 Ω \Omega per phase. If the line current is reduced by 20% due to power factor correction, determine the percentage reduction in copper losses.

  1. ((a))

    20%

  2. ((b))

    32%

  3. ((c))

    36%

  4. ((d))

    64%

Show Answer
Answer: ((a))

20%

24

Under which condition is corona loss in a transmission line minimum?

  1. ((a))

    Voltage is high

  2. ((b))

    Conductor surface is rough

  3. ((c))

    Weather is dry

  4. ((d))

    Air density is low

Show Answer
Answer: ((a))

Voltage is high

25

A transmission system becomes most economical under which operating condition?

  1. ((a))

    Voltage is low

  2. ((b))

    Current is high

  3. ((c))

    Voltage is high

  4. ((d))

    Resistance is high

Show Answer
Answer: ((a))

Voltage is low

26

Which type of transmission line is employed for voltage levels exceeding 33 kV?

  1. ((a))

    Underground cable

  2. ((b))

    Overhead transmission line

  3. ((c))

    Coaxial cable

  4. ((d))

    Twisted pair

Show Answer
Answer: ((a))

Underground cable

27

Kirchhoff's Voltage Law (KVL) results from the conservation law of:

  1. ((a))

    Charge

  2. ((b))

    Energy

  3. ((c))

    Momentum

  4. ((d))

    Mass

Show Answer
Answer: ((a))

Charge

28

Two 6Ω 6 \Omega and 3Ω 3 \Omega resistors are linked in parallel. What is the current passing through the 6Ω 6 \Omega resistor if the combination receives a total current of 9 A?

  1. ((a))

    6 A

  2. ((b))

    3 A

  3. ((c))

    4 A

  4. ((d))

    2 A

Show Answer
Answer: ((a))

6 A

29

Which of the following units represents the magnetic flux?

  1. ((a))

    Tesla

  2. ((b))

    Weber

  3. ((c))

    Henry

  4. ((d))

    Ampere-turn

Show Answer
Answer: ((a))

Tesla

30

Which of the following conditions must be satisfied for the Superposition Theorem to be applicable in an electrical network?

  1. ((a))

    The network must contain non-linear elements

  2. ((b))

    The network must be linear and bilateral

  3. ((c))

    The network must contain only passive elements

  4. ((d))

    The network must operate at a constant temperature

Show Answer
Answer: ((a))

The network must contain non-linear elements

31

A circuit contains only dependent sources and resistors. What is the value of the Thevenin equivalent voltage (Vth V_{th} ) looking into any pair of terminals?

  1. ((a))

    Infinite

  2. ((b))

    Equal to the supply voltage of the dependent source

  3. ((c))

    Zero

  4. ((d))

    Unity

Show Answer
Answer: ((a))

Infinite

32

For a network consisting of linear resistors and independent sources, if the load resistance is fixed and the source resistance is variable, maximum power is transferred to the load when:

  1. ((a))

    Source resistance equals load resistance

  2. ((b))

    Source resistance is minimum (ideally zero)

  3. ((c))

    Source resistance is maximum

  4. ((d))

    Source resistance is half the load resistance

Show Answer
Answer: ((a))

Source resistance equals load resistance

33

Which of the following methods is most effective for extending the range of a PMMC (Permanent Magnet Moving Coil) ammeter?

  1. ((a))

    Connecting a high resistance in series with the meter coil

  2. ((b))

    Connecting a low resistance shunt in parallel with the meter coil

  3. ((c))

    Connecting a capacitor in parallel with the meter coil

  4. ((d))

    Increasing the number of turns in the coil

Show Answer
Answer: ((a))

Connecting a high resistance in series with the meter coil

34

In a standard electrodynamometer-type wattmeter, how are the fixed coils and moving coils connected?

  1. ((a))

    Fixed coils in series with the load, moving coil in parallel with the supply

  2. ((b))

    Fixed coils in parallel with the load, moving coil in series with the supply

  3. ((c))

    Both fixed and moving coils are in series with the load

  4. ((d))

    Both fixed and moving coils are in parallel with the supply

Show Answer
Answer: ((a))

Fixed coils in series with the load, moving coil in parallel with the supply

35

The maximum torque of a three-phase induction motor is unaffected by:

  1. ((a))

    Supply voltage

  2. ((b))

    Rotor resistance

  3. ((c))

    Frequency

  4. ((d))

    Reactance

Show Answer
Answer: ((a))

Supply voltage

36

In a high-impedance circuit, the voltage across a resistor is measured using a voltmeter with a sensitivity of 20,000 V. How would the reading change if a voltmeter with a 1,000 V sensitivity were used in its place?

  1. ((a))

    The reading would be higher and more accurate

  2. ((b))

    The reading would be lower due to the loading effect

  3. ((c))

    The reading would remain exactly the same

  4. ((d))

    The reading would fluctuate unpredictably

Show Answer
Answer: ((a))

The reading would be higher and more accurate

37

In the measurement of power using an electrodynamometer wattmeter, the inductance of the pressure coil causes an error. At lagging power factors, this error results in the wattmeter reading being:

  1. ((a))

    Lower than the true power

  2. ((b))

    Higher than the true power

  3. ((c))

    Equal to the true power

  4. ((d))

    Zero

Show Answer
Answer: ((a))

Lower than the true power

38

The speed of a 4-pole, 50 Hz induction motor is 1440 rpm. What is the rotor current frequency?

  1. ((a))

    2 Hz

  2. ((b))

    50 Hz

  3. ((c))

    4 Hz

  4. ((d))

    1 Hz

Show Answer
Answer: ((a))

2 Hz

39

Phantom loading is employed for testing energy meters primarily to:

  1. ((a))

    Test the meter at voltages higher than rated

  2. ((b))

    Reduce power consumption during the test

  3. ((c))

    Check the insulation resistance

  4. ((d))

    Increase the starting torque

Show Answer
Answer: ((a))

Test the meter at voltages higher than rated

40

"Crawling" in a squirrel cage induction motor is characteristically observed at what fraction of the synchronous speed?

  1. ((a))

    13 \frac{1}{3}

  2. ((b))

    15 \frac{1}{5}

  3. ((c))

    17 \frac{1}{7}

  4. ((d))

    19 \frac{1}{9}

Show Answer
Answer: ((a))

13 \frac{1}{3}

41

When applying "Dynamic Braking" (Rheostatic Braking) to a 3-phase induction motor, which connection change is made?

  1. ((a))

    The phase sequence of the supply is reversed

  2. ((b))

    The stator is disconnected from AC and connected to a DC source

  3. ((c))

    Resistance is added to the rotor circuit while keeping AC supply

  4. ((d))

    One phase of the stator supply is opened

Show Answer
Answer: ((a))

The phase sequence of the supply is reversed

42

A double-cage induction motor is designed to achieve:

  1. ((a))

    High efficiency and low slip

  2. ((b))

    High starting torque and low starting current

  3. ((c))

    Low starting torque and high starting current

  4. ((d))

    Constant speed operation

Show Answer
Answer: ((a))

High efficiency and low slip

43

It is never advisable to start a DC series motor without a mechanical load on its shaft because:

  1. ((a))

    The speed will become dangerously high

  2. ((b))

    It will draw excessive current

  3. ((c))

    The back EMF will be zero

  4. ((d))

    The motor will not start

Show Answer
Answer: ((a))

The speed will become dangerously high

44

Which type of DC generator is most suitable for electric arc welding applications?

  1. ((a))

    DC Shunt Generator

  2. ((b))

    DC Series Generator

  3. ((c))

    Over-compound Generator

  4. ((d))

    Differential Compound Generator

Show Answer
Answer: ((a))

DC Shunt Generator

45

In a DC machine, the effect of armature reaction causes the Magnetic Neutral Axis (MNA) to shift:

  1. ((a))

    In the direction of rotation for a generator and opposite to rotation for a motor

  2. ((b))

    Opposite to the direction of rotation for a generator and in the direction for a motor

  3. ((c))

    In the direction of rotation for both

  4. ((d))

    Perpendicular to the Geometrical Neutral Axis (GNA) for both

Show Answer
Answer: ((a))

In the direction of rotation for a generator and opposite to rotation for a motor

46

During the commutation process in a DC machine, the "Reactance Voltage" responsible for sparking is produced due to:

  1. ((a))

    The resistance of the brush contact

  2. ((b))

    The self-inductance of the coil undergoing commutation

  3. ((c))

    The back EMF of the motor

  4. ((d))

    The friction between commutator and brush

Show Answer
Answer: ((a))

The resistance of the brush contact

47

When the series field flux in a DC compound generator opposes the shunt field flux, the device is referred to as:

  1. ((a))

    Cumulatively Compound

  2. ((b))

    Differentially Compound

  3. ((c))

    Series Generator

  4. ((d))

    Shunt Generator

Show Answer
Answer: ((a))

Cumulatively Compound

48

The average power absorbed by an impedence Z=30−j70Ω Z = 30 - j70\Omega when a voltage V=120∠0∘ V = 120\angle 0^\circ is applied across it is ________.

  1. ((a))

    189.12W

  2. ((b))

    94.56W

  3. ((c))

    37.24W

  4. ((d))

    86.91W

Show Answer
Answer: ((a))

189.12W

49

The rms value of the current waveform shown in image is ________.

  1. ((a))

    10A

  2. ((b))

    8.165A

  3. ((c))

    5.77A

  4. ((d))

    5A

Show Answer
Answer: ((a))

10A

50

The rms value of the current waveform shown in figure is ________.

  1. ((a))

    2A

  2. ((b))

    2.30A

  3. ((c))

    4A

  4. ((d))

    2.82A

Show Answer
Answer: ((a))

2A

51

The amount of average power dissipated in a 10 Ω resisitor when a voltage waveform V(t) V(t) is applied across it is ________.

  1. ((a))

    5W

  2. ((b))

    0.5W

  3. ((c))

    25W

  4. ((d))

    2.5W

Show Answer
Answer: ((a))

5W

52

A series connected load draws a current i(t)=4cos(100πt+10∘)A i(t) = 4cos(100\pi t + 10^\circ)A when the applied voltage is V(t)=120cos(100πt−20∘)V V(t) = 120cos(100\pi t - 20^\circ)V . The power factor of the load is ________.

  1. ((a))

    0.866

  2. ((b))

    0.750

  3. ((c))

    0.555

  4. ((d))

    0.707

Show Answer
Answer: ((a))

0.866

53

The power factor of the load whose impedance is Z=60+j40Ω Z = 60 + j40\Omega when the applied voltage is v(t)=15cos(377t+10∘)V v(t) = 15cos(377t + 10^\circ)V is ________.

  1. ((a))

    0.832

  2. ((b))

    0.600

  3. ((c))

    0.707

  4. ((d))

    0.554

Show Answer
Answer: ((a))

0.832

54

The voltage across a load is v(t)=60cos(ωt−10∘)V v(t) = 60cos(\omega t - 10^\circ)V and the current through the element in the direction of the voltage drop is i(t)=1.5cos(ωt+50∘)A i(t) = 1.5cos(\omega t + 50^\circ)A . The apparent power is ________.

  1. ((a))

    90VA

  2. ((b))

    63.63VA

  3. ((c))

    45VA

  4. ((d))

    50VA

Show Answer
Answer: ((a))

90VA

55

The average power supplied by the source is ________.

  1. ((a))

    118W

  2. ((b))

    160W

  3. ((c))

    99.2W

  4. ((d))

    126W

Show Answer
Answer: ((a))

118W

56

The average value of the non-sinosoidal wave V(t)=100+50sin(ωt)+25sin(2ωt) V(t) = 100 + 50sin(\omega t) + 25sin(2\omega t) is ________.

  1. ((a))

    100V

  2. ((b))

    87.5V

  3. ((c))

    125V

  4. ((d))

    150V

Show Answer
Answer: ((a))

100V

57

The average value of the non-sinosoidal wave, i(t)=3+2sin(ωt−53∘)+0.8sin(2ωt−70∘) i(t) = 3 + 2sin(\omega t - 53^\circ) + 0.8sin(2\omega t - 70^\circ) is ________.

  1. ((a))

    1.93A

  2. ((b))

    3A

  3. ((c))

    9A

  4. ((d))

    4.5A

Show Answer
Answer: ((a))

1.93A

58

Find the no-load power factor of a transformer on no-load having an induced emf of 230V (rms), draws a current of 2A(rms) and has a core loss of 50W.

  1. ((a))

    83.76

  2. ((b))

    1

  3. ((c))

    0.108

  4. ((d))

    10.8

Show Answer
Answer: ((a))

83.76

59

A 3300/250V, 50Hz, Single phase transformer is having 70 turns on LV side. Find the number of turns on HV side.

  1. ((a))

    924

  2. ((b))

    920

  3. ((c))

    928

  4. ((d))

    5

Show Answer
Answer: ((a))

924

60

Find the value of magnetizing component of no load current for a 230/110V single phase transformer, having core loss of 110W. It takes a input of 350VA at no load and rated voltage.

  1. ((a))

    1.44A

  2. ((b))

    0.478A

  3. ((c))

    1.52A

  4. ((d))

    2.11A

Show Answer
Answer: ((a))

1.44A

61

Find the voltage regulation of transformer at full load having reactance of 5% and resistance of 2% with a lagging power factor of 0.8.

  1. ((a))

    0.46%

  2. ((b))

    0.38%

  3. ((c))

    3.8%

  4. ((d))

    4.6%

Show Answer
Answer: ((a))

0.46%

62

A 2000/400V, 10KVA transformer having ohmic loss of 1% and reactance drop of 9%. Find its regulation at unity power factor.

  1. ((a))

    0

  2. ((b))

    1

  3. ((c))

    3.8

  4. ((d))

    2.2

Show Answer
Answer: ((a))

0

63

In the circuit shown, a 120VDC source is connected to a resistive network. A 12Ω resistor is connected in series with the source and leads to a junction. Calculate the terminal voltage VAB V_{AB} .

<br>

From this junction:

· A 20Ω resistor is connected to terminal A

· A 15Ω resistor is connected vertically to terminal B

<br>

Assume all resistors are ideal.

  1. ((a))

    65.23

  2. ((b))

    66.12V

  3. ((c))

    66.67

  4. ((d))

    66.15

Show Answer
Answer: ((a))

65.23

64

Three resistors of 8Ω each are connected in parallel. What is the equivalent resistance?

  1. ((a))

    2.67Ω

  2. ((b))

    3.01Ω

  3. ((c))

    3Ω

  4. ((d))

    1.01Ω

Show Answer
Answer: ((a))

2.67Ω

65

What is the power consumed by a 40Ω resistor connected directly to a 12V battery?

  1. ((a))

    3.6V

  2. ((b))

    3.6W

  3. ((c))

    2.6W

  4. ((d))

    2.5V

Show Answer
Answer: ((a))

3.6V

66

A phasor voltage V=100∠30∘ V V = 100\angle 30^{\circ} \text{ V} is applied across an impedance Z=20∠35∘ Ω Z = 20\angle 35^{\circ} \text{ }\Omega . Obtain an expression for the instantaneous power and then find the value of the average power fed to the impedance.

Given: ω=100 rad \omega = 100 \text{ rad}

  1. ((a))

    450W

  2. ((b))

    470W

  3. ((c))

    410W

  4. ((d))

    515W

Show Answer
Answer: ((a))

450W

67

A charge of 12 nC is enclosed inside a closed surface. Calculate the electric flux through this surface (ε0=8.854×10−12F/m \varepsilon_0 = 8.854 \times 10^{-12} F/m ).

  1. ((a))

    9×102Nm2/C 9 \times 10^2 Nm^2/C

  2. ((b))

    452Nm2/C 452 Nm^2/C

  3. ((c))

    904Nm2/C 904 Nm^2/C

  4. ((d))

    1.356×103N 1.356 \times 10^3 N

Show Answer
Answer: ((a))

9×102Nm2/C 9 \times 10^2 Nm^2/C

68

What is the speed of propagation for an electromagnetic wave in free space?

  1. ((a))

    3×107m/s 3 \times 10^7 m/s

  2. ((b))

    1.5×108m/s 1.5 \times 10^8 m/s

  3. ((c))

    3×108m/s 3 \times 10^8 m/s

  4. ((d))

    9×108m/s 9 \times 10^8 m/s

Show Answer
Answer: ((a))

3×107m/s 3 \times 10^7 m/s

69

A lossless transmission line is 1 m long and operates at 500 MHz. Find its characteristic impedance. The line parameters are:

<br>

· L = 0.4μH/m 0.4 \mu H/m

· C = 80pF/m 80 pF/m

  1. ((a))

    67.01Ω 67.01 \Omega

  2. ((b))

    70.7Ω 70.7 \Omega

  3. ((c))

    80Ω 80 \Omega

  4. ((d))

    105Ω 105 \Omega

Show Answer
Answer: ((a))

67.01Ω 67.01 \Omega

70

Two transmission lines connected end-to-end: Line 1 (40 m, 0.08 dB/m attenuation), Line 2 (25 m, 0.2 dB/m attenuation), with a 2 dB joint loss. What percentage of input power reaches the output?

  1. ((a))

    9.5%

  2. ((b))

    8.7%

  3. ((c))

    10.2%

  4. ((d))

    12.5%

Show Answer
Answer: ((a))

9.5%

71

A solenoid of 80cm length carries 0.8A current. Calculate the number of turns required for a magnetic field strength H=600AT/m H = 600AT/m at the center (ideal long solenoid approximation).

  1. ((a))

    400

  2. ((b))

    600

  3. ((c))

    800

  4. ((d))

    1000

Show Answer
Answer: ((a))

400

72

Which of the following is NOT a standard excitation system for synchronous machines?

  1. ((a))

    Rotating rectifier (AC) excitation system

  2. ((b))

    Static excitation system

  3. ((c))

    Brushless excitation system

  4. ((d))

    Heat excitation system

Show Answer
Answer: ((a))

Rotating rectifier (AC) excitation system

73

Determine the maximum output at given excitation, if a 3 - phase, 11 - kv, 6MVA Y-connected alternator has synchronous impedance of (1+j10) (1 + j10) ohm per phase. Its excitation is such that the generated line EMF is 14kV. If the alternator is connected to infinite bus-bars.

  1. ((a))

    16.01MW

  2. ((b))

    15.405MW

  3. ((c))

    14.21MW

  4. ((d))

    16.656MW

Show Answer
Answer: ((a))

16.01MW

74

If a 105 - MVA, 10 - kV, 0.8 - PF - lagging, 50 - Hz and two-pole Y-connected synchronous generator has a per-unit synchronous reactance of 1.2 and a per-unit armature resistance of 0.02. then what is the torque angle δ \delta at these conditions?

  1. ((a))

    28.6°

  2. ((b))

    25.4°

  3. ((c))

    45.1°

  4. ((d))

    18.9°

Show Answer
Answer: ((a))

28.6°

75

A power station has a load factor of 0.7 and a maximum demand of 14, 000kW . What is its average load?

  1. ((a))

    9800kW

  2. ((b))

    20000kW

  3. ((c))

    2000kW

  4. ((d))

    98000kW

Show Answer
Answer: ((a))

9800kW

76

Maintenance and repair costs of a power plant are classified as:

  1. ((a))

    Fixed cost

  2. ((b))

    Interest on capital

  3. ((c))

    Running cost

  4. ((d))

    Amortization of the capital

Show Answer
Answer: ((a))

Fixed cost

77

In a hydroelectric power plant, which component typically has the highest capital cost?

  1. ((a))

    Civil structures (dams, tunnels, etc.)

  2. ((b))

    Land acquisition

  3. ((c))

    Transmission lines

  4. ((d))

    Electromechanical equipment (turbines, generators, etc.)

Show Answer
Answer: ((a))

Civil structures (dams, tunnels, etc.)

78

A 300km long, three-phase transmission line operates at 400kV and 50Hz. The inductance of the line is 0.97mH per kilometer per phase, and the capacitance is 0.0115µF per kilometer per phase. Assuming the line is lossless, calculate the characteristic impedance Zc Z_{c} .

  1. ((a))

    290.43Ω

  2. ((b))

    200.43Ω

  3. ((c))

    177.36Ω

  4. ((d))

    150.15Ω

Show Answer
Answer: ((a))

290.43Ω

79

When reverse bias is applied to a p-n junction diode, it:

  1. ((a))

    lowers the potential barrier.

  2. ((b))

    rasies the potential barrier.

  3. ((c))

    greatly decreases the minority carrier current.

  4. ((d))

    greatly increases the minority carrier current.

Show Answer
Answer: ((a))

lowers the potential barrier.

80

When a positive DC voltage is applied to the n-side relative to the p-side of a PN junction diode, the diode is under:

  1. ((a))

    Forward bias

  2. ((b))

    Reverse bias

  3. ((c))

    Zero bias

  4. ((d))

    Neutral bias

Show Answer
Answer: ((a))

Forward bias

81

The main purpose of a clamper circuit is to:

  1. ((a))

    Introduce a DC level into the AC signal.

  2. ((b))

    Suppress variations in signal voltage

  3. ((c))

    Raise +ve half cycle of the signal.

  4. ((d))

    Lower -ve half cycle of the signal.

Show Answer
Answer: ((a))

Introduce a DC level into the AC signal.

82

Without a DC source, a clipper circuit acts like a:

  1. ((a))

    Clamper

  2. ((b))

    Chopper

  3. ((c))

    Rectifier

  4. ((d))

    Demodulator

Show Answer
Answer: ((a))

Clamper

83

A single-phase diode bridge rectifier supplies a highly inductive load (ripple-free current). The AC supply-side current waveform is:

  1. ((a))

    Sinusoidal

  2. ((b))

    Constant dc

  3. ((c))

    Square

  4. ((d))

    Triangular

Show Answer
Answer: ((a))

Sinusoidal

84

What is the SI unit for luminous flux?

  1. ((a))

    Candela

  2. ((b))

    Lumen

  3. ((c))

    Lumens/m2

  4. ((d))

    Lux

Show Answer
Answer: ((a))

Candela

85

For an isotropic light source of luminous intensity 1 candela, what is the total luminous flux emitted in all directions?

  1. ((a))

    π\pi lumens

  2. ((b))

    2π2\pi lumens

  3. ((c))

    3π3\pi lumens

  4. ((d))

    4π4\pi lumens

Show Answer
Answer: ((a))

π\pi lumens

86

A three-phase induction motor has maximum torque to full-load torque ratio of 2.5 : 1, with rotor resistance 0.5Ω/phase\Omega/phase and reactance 4Ω/phase\Omega/phase. Find the star-delta starting torque to full-load torque ratio.

  1. ((a))

    1.503

  2. ((b))

    0.205

  3. ((c))

    5.73

  4. ((d))

    9.83

Show Answer
Answer: ((a))

1.503

87

A 220V shunt motor has armature resistance 0.4Ω\Omega, takes 20A on full load at 750rpm. With an additional 0.6Ω\Omega in the armature circuit, find the stalling torque to full-load torque ratio.

  1. ((a))

    12.2

  2. ((b))

    13

  3. ((c))

    21

  4. ((d))

    11

Show Answer
Answer: ((a))

12.2

88

The rotor of an 8 - pole, 50Hz, 3 - phase induction motor has a rotor resistance of 0.4Ω/phase\Omega/phase and runs at a speed of 720rpm. For a constant load torque, calculate the additional rotor resistance/phase that must be inserted to reduce the speed by 25%.

  1. ((a))

    1.8

  2. ((b))

    2.1

  3. ((c))

    2.4

  4. ((d))

    4.8

Show Answer
Answer: ((a))

1.8

89

A cascade set of two induction motors (A : 6poles, B : 8poles) is supplied from a 60Hz 3 - phase supply. Calculate the synchronous speed of the cumulative cascade set.

  1. ((a))

    514.3 rpm

  2. ((b))

    554 rpm

  3. ((c))

    578 rpm

  4. ((d))

    600 rpm

Show Answer
Answer: ((a))

514.3 rpm

90

Which of the following is the most important reason for the preference of AC motors over DC motors in modern electric drives?

  1. ((a))

    AC motors produce higher starting torque

  2. ((b))

    AC motors do not require speed control

  3. ((c))

    AC power can be transmitted easily with low line losses

  4. ((d))

    AC motors are only used for constant speed applications

Show Answer
Answer: ((a))

AC motors produce higher starting torque

91

Which of the following is NOT a function of the power modulator in an electric drive system?

  1. ((a))

    Regulating motor current during starting and braking

  2. ((b))

    Selecting motoring or braking operation

  3. ((c))

    Converting source energy to suitable form for the motor

  4. ((d))

    Producing mechanical torque directly

Show Answer
Answer: ((a))

Regulating motor current during starting and braking

92

Which of the following is the primary reason electric heating is more efficient than non-electric heating methods?

  1. ((a))

    Electric heating produces higher temperatures

  2. ((b))

    Electric heating requires less floor area

  3. ((c))

    A larger percentage of heat produced is utilized

  4. ((d))

    Electric heating equipment is cheaper

Show Answer
Answer: ((a))

Electric heating produces higher temperatures

93

Heat transfer without actual movement of molecules, dependent on temperature gradient, occurs by:

  1. ((a))

    Convection

  2. ((b))

    Conduction

  3. ((c))

    Radiation

  4. ((d))

    Advection

Show Answer
Answer: ((a))

Convection

94

According to Stefan-Boltzmann law, the net radiant heat transfer between two bodies is proportional to:

  1. ((a))

    Difference of temperatures

  2. ((b))

    Square of temperature difference

  3. ((c))

    Difference of fourth power of absolute temperatures

  4. ((d))

    Product of temperatures

Show Answer
Answer: ((a))

Difference of temperatures

95

Which property of a heating element material enables precise temperature control during its operation?

  1. ((a))

    High melting point

  2. ((b))

    High emissivity

  3. ((c))

    Low temperature coefficient of resistance

  4. ((d))

    High mechanical strength

Show Answer
Answer: ((a))

High melting point

96

A voltmeter with a 0-50V range has an accuracy of ±1% of full-scale. What is the percentage limiting error when the instrument reads 15V?

  1. ((a))

    3.33%

  2. ((b))

    7.5%

  3. ((c))

    1.5%

  4. ((d))

    0.3%

Show Answer
Answer: ((a))

3.33%

97

A D' Arsonval galvanometer has flux denisty= 8×10−3 Wb/m2 8 \times 10^{-3} \text{ Wb/m}^2 , number of turns=300, length of coil=15mm, width of coil=30 mm, spring constant= 2.5×10−9 Nm/rad 2.5 \times 10^{-9} \text{ Nm/rad} , moment of intertia= 10×10−9 Kg - m2 10 \times 10^{-9} \text{ Kg - m}^2 , damping constant= 2×10−9 Nm/rad - s−1 2 \times 10^{-9} \text{ Nm/rad - s}^{-1} , resistance of coil= 80Ω . What is the deflection of the galvanometer for a current of 1μA ?

  1. ((a))

    0.432 rad

  2. ((b))

    0.215 rad

  3. ((c))

    0.864 rad

  4. ((d))

    1.02 rad

Show Answer
Answer: ((a))

0.432 rad

98

A voltmeter with a full-scale range of 0-100V has a specified accuracy of ±1% of full-scale value. If the instrument indicates 50V, what is the maximum possible percentage error in the reading?

  1. ((a))

    1%

  2. ((b))

    2%

  3. ((c))

    0.5%

  4. ((d))

    4%

Show Answer
Answer: ((a))

1%

99

Which of the following is classified as an integrating instrument in electrical measurements?

  1. ((a))

    Ammeter

  2. ((b))

    Voltmeter

  3. ((c))

    Wattmeter

  4. ((d))

    Energy Meter

Show Answer
Answer: ((a))

Ammeter

100

How is a galvanometer protected from mechanical shock and induced EMFs during transport?

  1. ((a))

    By connecting a critical damping resistance across its terminals

  2. ((b))

    By short-circuiting its terminals

  3. ((c))

    By keeping its terminals open-circuited

  4. ((d))

    By connecting a capacitor across its terminals

Show Answer
Answer: ((a))

By connecting a critical damping resistance across its terminals

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