Explore topic-wise MCQs in Electrical Engineering Questions.

This section includes 210 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering Questions knowledge and support exam preparation. Choose a topic below to get started.

1.

What is the usual rating of a synchronous induction motor?
A. Below 25 kW
B. Below 5 kW
C. Above 30 kW
D. Above 100 kW
Answer» B. Below 5 kW
Discussion
2.

What will be the rating of heater if the machine to be dried is less than 500 kW?
A. 1.5 - 3 % of the machine rating
B. 3.5 % of the machine rating
C. 5 % of the machine rating
D. 5.5 % of the machine rating
Answer» C. 5 % of the machine rating
Discussion
3.

What designation is used for non sparking type of motor?
A. Ex(d)
B. Ex(p)
C. Ex(N)
D. Ex(e)
Answer» D. Ex(e)
Discussion
4.

What is the minimum life span of a galvanised steel structure?
A. 15 years
B. 25 years
C. 40 years
D. 80 years
Answer» D. 80 years
Discussion
5.

Which gel ensures the dryness of the incoming air in the breather?
A. Potassium gel
B. Silica gel
C. Carbon gel
D. All of these
Answer» C. Carbon gel
Discussion
6.

On what type of bearing does the heavy power electrical machine rotate?
A. Ball bearing
B. Sleeve bearing
C. Roller bearing
D. Any of these
Answer» C. Roller bearing
Discussion
7.

Which types of bearings are used for fractional HP motors? i. Sleeve bearing ii. Ball bearing iii. Roller bearing iv. Needle bearing
A. i & ii only
B. ii & iii only
C. iii & iv only
D. i, ii, iii & iv
Answer» B. ii & iii only
Discussion
8.

Which among these systems is an auxiliary plant in a power system?
A. Fuel oil system
B. Raw water system
C. Transformer oil plant
D. All of these
E. None of these
Answer» E. None of these
Discussion
9.

Which type of insulation is preferred if the maximum temperature is 130°?
A. Class A
B. Class B
C. Class E
D. Class F
Answer» C. Class E
Discussion
10.

Which circuit among the following requires a supply of 48 V DC source?
A. Trip coils and closing coils
B. Micro wave protection and communication
C. Dc measuring instruments
D. All of these
E. None of these
Answer» C. Dc measuring instruments
Discussion
11.

Which among these require a low voltage DC source?
A. Telemetering and communication
B. Uninterrupted power supply
C. The protective relays and the trip circuit
D. All of these
E. None of these
Answer» E. None of these
Discussion
12.

A primary cell is chemically _____________________.
A. Irreversible
B. Reversible
C. Reversible only once
D. Reversible upto five times
Answer» B. Reversible
Discussion
13.

How is an electrochemical cell rated if ‘n’ cells are connected in series?
A. Ah (ampere hour)
B. n Ah
C. Ah / n
D. nV / Ah
Answer» C. Ah / n
Discussion
14.

Which element is used as an anode in a dry cell?
A. Carbon
B. Zinc
C. Lead
D. Zinc sulphate
Answer» B. Zinc
Discussion
15.

Which test is a special type of test performed on the transformers?
A. Partial discharge
B. Temperature rise test
C. Ratio and polarity test
D. Noise level test
Answer» B. Temperature rise test
Discussion
16.

What are the types of voltage transformers?
A. Electromagnetic potential transformers
B. Capacitor potential transformers
C. Inductor and resistor potential transformers
D. Only (a) and (b)
E. All of these
Answer» E. All of these
Discussion
17.

What will be the relay current range in amperes for a 3 phase 50 Hz 12.5 Hp 440 V motor?
A. 13 – 20 A
B. 20 – 30 A
C. 30 – 45 A
D. 6 – 13 A
Answer» B. 20 – 30 A
Discussion
18.

Which among these is not a type test performed on the current transformers?
A. Overvoltage inter turn tests
B. Short time current tests
C. Temperature rise tests
D. Error measurement
Answer» B. Short time current tests
Discussion
19.

Which among these is the essential part for a CT?
A. Insulation over the core by tape
B. Support porcelain or epoxy insulator
C. Synthetic resin or oil insulation
D. All of these
E. None of these
Answer» E. None of these
Discussion
20.

What is the main cause of harmful vibrations in the machine?
A. Mechanically unbalanced rotor
B. Bent or cracked shaft
C. An excessively pulsating load
D. All of these
E. None of these
Answer» E. None of these
Discussion
21.

Which among these is / are the abnormal operating conditions caused due to mechanical overloads?
A. Sustained overloads
B. Prolonged starting or locked rotor
C. Stalling
D. Only (a) and (b)
E. All of these
Answer» F.
Discussion
22.

What protection is preferred for preventing rotor faults?
A. Thermal relay
B. HRC fuses
C. Instantaneous over current relay
D. Differential protection
Answer» D. Differential protection
Discussion
23.

On what factors does the size of the induction motor depend?
A. Power output
B. Frequency
C. Speed of rotation
D. Both (A) and (C)
E. All of these
Answer» E. All of these
Discussion
24.

Which element is used as the cathode in lead acid battery?
A. Sponge lead
B. Lead peroxide
C. Rubber mixed with lead
D. None of these
Answer» B. Lead peroxide
Discussion
25.

On what factors is the rated voltage selected for an induction motor?
A. Motor rating
B. Starting current
C. Fault levels of supply
D. All of these
E. None of these
Answer» E. None of these
Discussion
26.

What is the temperature limit for the storage of machines at site before installation?
A. Temperature above + 25 °C
B. Temperature above + 5 °C
C. Temperature less than 10 °C
D. Temperature above 15 °C
Answer» E.
Discussion
27.

What is the maximum rated output for an engine driven synchronous generator?
A. 10 MW
B. 20 MW
C. 50 MW
D. 100 MW
Answer» C. 50 MW
Discussion
28.

What is / are the functions of sealing device used along with bearings?
A. To prevent leakage of oil from the bearing housing
B. To prevent dust, water, dirt etc from entering the bearing housing
C. Both (a) and (b)
D. None of these
Answer» D. None of these
Discussion
29.

Which type of cooling system is preferred for turbo alternators?
A. Forced air
B. Hydrogen
C. Water cooled
D. Only (b) & (c)
E. All of these
Answer» F.
Discussion
30.

What is / are the different type(s) of excitation system of a synchronous motor?
A. Slip ring type
B. Brushless type
C. Both (A) and (B)
D. None of these
Answer» D. None of these
Discussion
31.

Which type of rotor is used by Hydro Generators?
A. Salient pole
B. Cylindrical rotor
C. Both (A) and (B)
D. None of these
Answer» B. Cylindrical rotor
Discussion
32.

How is the maximum discharge current calculated?
A. Maximum discharge current = (continuous load + rated voltage) / (short time load)
B. Maximum discharge current = (continuous load + short time load) / (rated voltage)
C. Maximum discharge current = rated voltage ( continuous load + short time load)
D. Maximum discharge current = (short time load + rated voltage) / (continuous load)
Answer» C. Maximum discharge current = rated voltage ( continuous load + short time load)
Discussion
33.

Which type of rotor is designed for synchronous motor rating upto 5 kW?
A. Squirrel cage rotor
B. Slip ring rotor
C. Salient pole rotor
D. Cylindrical rotor
Answer» B. Slip ring rotor
Discussion
34.

At which power angle is the pull out torque developed in the synchronous motor?
A. δ = 45 °
B. δ = 30 °
C. δ = 70 °
D. δ = 90 °
Answer» D. δ = 90 °
Discussion
35.

What is rated burden in current transformers?
A. The specified limits of ratio error and phase angle error.
B. The ratio of rated short time current to rated primary current.
C. A specification by the manufacturer at which CT performs with the specified accuracy.
D. The phase angle between primary current vector and reversed secondary current vector.
Answer» D. The phase angle between primary current vector and reversed secondary current vector.
Discussion
36.

What type of circuits use static rectifiers?
A. Circuits where storage batteries are not essential
B. Circuits where storage batteries are essential
C. Used in all the AC and DC circuits along with batteries
D. Used in AC circuits only
Answer» B. Circuits where storage batteries are essential
Discussion
37.

Which solutions are added into the lead acid battery?
A. Distilled water
B. Acid water solution
C. Transformer oil
D. Both (a) and (b)
Answer» E.
Discussion
38.

What is over current factor?
A. The specified limits of ratio error and phase angle error.
B. The ratio of rated short time current to rated primary current.
C. A specification by the manufacturer at which CT performs with the specified accuracy.
D. The phase angle between primary current vector and reversed secondary current vector.
Answer» C. A specification by the manufacturer at which CT performs with the specified accuracy.
Discussion
39.

Which charging method is employed for charging a Lead acid battery?
A. Tapper charging
B. Constant voltage charging
C. Two rate method of charging
D. All of these
E. None of these
Answer» E. None of these
Discussion
40.

What is the value of open circuit voltage in a dry cell?
A. 2.5 V
B. 2.8 V
C. 1.6 V
D. 3.2 V
Answer» D. 3.2 V
Discussion
41.

Which among these tests are performed periodically?
A. Repair tests
B. Maintenance testing
C. Manufacturers tests
D. All of these
E. None of these
Answer» C. Manufacturers tests
Discussion
42.

What is the minimum deionisation time necessary for auto reclosing in a circuit breaker if the voltage of transmission line is 132 kV?
A. 5 cycles
B. 14 cycles
C. 9 cycles
D. 13 cycles
Answer» D. 13 cycles
Discussion
43.

What is the function of control cables?
A. For protective circuits between C Ts, V Ts, and relays
B. To sense the fault and close trip circuit for circuit breaker
C. Opening and fault clearing
D. All of these
E. None of these
Answer» B. To sense the fault and close trip circuit for circuit breaker
Discussion
44.

Which among the following device is connected to provide protection against phase to earth insulation failure?
A. Earth fault relay connected in neutral to earth circuit.
B. Earth fault relay connected in three phase residual secondary circuit of C T secondaries
C. Differential protection
D. All of these
E. None of these
Answer» E. None of these
Discussion
45.

Which enclosures are preferred for preventing entry of falling water or dirt?
A. Totally enclosed
B. Drip splash or hose proof
C. Open end bracket
D. All of these
Answer» C. Open end bracket
Discussion
46.

Which among these gases is not used as a coolant?
A. Hydrogen
B. Nitrogen
C. Carbon dioxide
D. Helium
Answer» E.
Discussion
47.

What does IC 01 describe?
A. Self cooled open machine fan mounted on the shaft
B. Totally enclosed machine frame cooled no extra fan
C. Totally enclosed machines frame and tubes externally and internal fault.
D. Inlet pipe self ventilated machines fan mounted on the shaft.
Answer» B. Totally enclosed machine frame cooled no extra fan
Discussion
48.

What is the maximum permissible voltage drop that can be sustained while starting an electrical rotating machine?
A. 15 – 20 % of the rated voltage
B. 20 – 25 % of the rated voltage
C. 5 – 10 % of the rated voltage
D. 0 – 5 % of the rated voltage
Answer» B. 20 – 25 % of the rated voltage
Discussion
49.

Which among the following cooling system is employed for large machine?
A. Radial flow
B. Axial flow
C. Combined radial and axial cooling
D. Multiple inlet cooling
Answer» D. Multiple inlet cooling
Discussion
50.

Which connection is preferred for connecting line tap changers to transformers?
A. 3 wire 3 phase AC system
B. 3 wire 2 phase AC system
C. 4 wire 3 phase AC system
D. All of these
Answer» D. All of these
Discussion