Explore topic-wise MCQs in Electrical Engineering.

This section includes 198 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering knowledge and support exam preparation. Choose a topic below to get started.

1.

The active materials on the positive and negative plates of a fully charged lead-acid battery are

A. lead and lead peroxide
B. lead sulphate and lead
C. lead peroxide and lead
D. none of the above
Answer» D. none of the above
Discussion
2.

The current flow through electrolyte is due to the movement of

A. ions
B. holes
C. electrons
D. none of the above
Answer» B. holes
Discussion
3.

Which of the following factors adversely affects the capacity of the leadacid battery ?

A. Temperature of surroundings
B. Specific gravity of electrolyte
C. Rate of discharge
D. All of the above
Answer» E.
Discussion
4.

48 ampere-hour capacity would deliver a current of

A. 48 amperes for 1 hour
B. 24 amperes for 2 hours
C. 8 amperes for 6 hours
D. 6 amperes for 8 hours
Answer» E.
Discussion
5.

Persons preparing electrolyte should wear

A. goggles or other face shield
B. rubber
C. rubber boots and gloves
D. all above safety devices
Answer» E.
Discussion
6.

Capacity of dry cells is

A. more when it is supplying current for intermittent periods
B. more when it is supplying current for continuous periods
C. unaffected by the type of discharge
D. none of the above
Answer» B. more when it is supplying current for continuous periods
Discussion
7.

Which among the following constitutes the major load for an automobile battery ?

A. Brake light
B. Self starter
C. Parking lights
D. Spark plugs
Answer» C. Parking lights
Discussion
8.

The following indicate that battery on charge has attained full charge

A. colour of electrode
B. gassing
C. specific gravity
D. all above
Answer» E.
Discussion
9.

Lead-acid cell has a life of nearly charges and discharges

A. 500
B. 700
C. 1000
D. 1250
Answer» E.
Discussion
10.

Chargmg of sulphated battery produces ____ heat.

A. no
B. very little
C. less
D. more
Answer» E.
Discussion
11.

During the charging of a lead-acid cell

A. its voltage increases
B. it gives out energy
C. its cathode becomes dark chocolate brown in colour
D. specific gravity of H₂SO₄ decreases
Answer» B. it gives out energy
Discussion
12.

Internal resistance of a cell is due to

A. resistance of electrolyte
B. electrode resistance
C. surface contact resistance between electrode and electrolyte
D. all above
Answer» E.
Discussion
13.

The ampere-hour efficiency of a leadacid cell is normally between

A. 20 to 30%
B. 40 to 50%
C. 60 to 70%
D. 90 to 95%
Answer» E.
Discussion
14.

The effect of sulphation is that the internal resistance

A. increases
B. decreases
C. remains same
D. none of the above
Answer» B. decreases
Discussion
15.

Battery charging equipment is generally installed

A. In well ventilated location
B. In clean and dry place
C. As near as practical to the battery being charged
D. In location having all above features
Answer» E.
Discussion
16.

The e.m.f. of an Edison cell, when fully charged, is nearly

A. 1.4 V
B. 1 V
C. 0.9 V
D. 0.8 V
Answer» B. 1 V
Discussion
17.

The capacity of a battery is expressed in terms of

A. current rating
B. voltage rating
C. ampere-hour rating
D. none of the above
Answer» D. none of the above
Discussion
18.

It is noticed that during discharging the following does not happen

A. both anode and cathode become PbS04
B. specific gravity of H?SO? decreases
C. voltage of the cell decreases
D. the cell absorbs energy
Answer» E.
Discussion
19.

Hydrogen evolved during charging produces explosive mixture when it is more than

A. 2%
B. 4%
C. 6%
D. 8%
Answer» E.
Discussion
20.

Undercharging

A. Reduces specific gravity of the electrolyte
B. Increases specific gravity of the electrolyte
C. Produces excessive gassing
D. Increases the temperature
Answer» B. Increases specific gravity of the electrolyte
Discussion
21.

When a lead-acid battery is in fully charged condition, the color of its positive plate is

A. dark grey
B. brown
C. dark brown
D. none of above
Answer» D. none of above
Discussion
22.

In a lead-acid battery the energy is stored in the form of

A. charged ions
B. chemical energy
C. electrostatic energy
D. electromagnetic energy
Answer» C. electrostatic energy
Discussion
23.

Which of the following primary cells has the lowest voltage ?

A. Lithium
B. Zinc-chloride
C. Mercury
D. Carbon-zinc
Answer» D. Carbon-zinc
Discussion
24.

Local action in a battery is indicated by

A. excessive gassing under load conditions
B. excessive drop in the specific gravity of electrolyte even when the cell is on open circuit
C. both (A) and (B)
D. none of the above
Answer» E.
Discussion
25.

Specific gravity of electrolyte in Edison cell is

A. 0.8
B. 0.95
C. 1.1
D. 1.21
Answer» E.
Discussion
26.

In a battery cover is placed over the element and sealed to the top of the battery container. This is done

A. to reduce evaporation of water from electrolyte
B. to exclude dirt and foreign matter from the electrolyte
C. to discharge both of the above functions
D. to discharge none of the above functions
Answer» D. to discharge none of the above functions
Discussion
27.

The output voltage of a charger is

A. less than the battery voltage
B. higher than the battery voltage
C. the same as the battery voltage
D. none of the above
Answer» C. the same as the battery voltage
Discussion
28.

A dead storage battery can be revived by

A. adding distilled water
B. adding so-called battery restorer
C. a dose of H₂SO₄
D. none of the above
Answer» E.
Discussion
29.

The storage battery generally used in electric power station is

A. nickel-cadmium battery
B. zinc-carbon battery
C. lead-acid battery
D. none of the above
Answer» D. none of the above
Discussion
30.

Internal short circuits are caused by

A. breakdown of one or more separators
B. excess accumulation of sediment at the bottom of the cell
C. both (A) and (B)
D. none of the above
Answer» D. none of the above
Discussion
31.

In a lead-acid cell dilute sulfuric acid (electrolyte) approximately comprises the following

A. one part H2O, three parts H₂SO₄
B. two parts H2O, two parts H₂SO₄
C. three parts H2O, one part H₂SO₄
D. all H₂SO₄
Answer» D. all H₂SO₄
Discussion
32.

“The mass of an ion liberated at an electrode is directly proportional to the quantity of electricity”.The above statement is associated with

A. Newton’s law
B. Faraday’s law of electromagnetic
C. Faraday’s law of electrolysis
D. Gauss’s law
Answer» D. Gauss’s law
Discussion
33.

Over charging

A. produces excessive gassing
B. loosens the active material
C. increases the temperature resulting in buckling of plates
D. all above
Answer» E.
Discussion
34.

Ampere hour capacity of an industrial battery is based on ____ hours discharge rate.

A. 8
B. 12
C. 16
D. 24
Answer» B. 12
Discussion
35.

When two batteries are connected in parallel, it should be ensured that

A. they have same e.m.f.
B. they have same make
C. they have same ampere-hour capacity
D. they have identical internal resistance
Answer» B. they have same make
Discussion
36.

Battery container should be acid resistance, therefore it is made up of

A. glass
B. plastic
C. wood
D. all above
Answer» E.
Discussion
37.

The watt-hour efficiency of a lead-acid cell varies between

A. 25 to 35%
B. 40 to 60%
C. 70 to 80%
D. 90 to 95%
Answer» D. 90 to 95%
Discussion
38.

The capacity of a lead-acid cell is measured in

A. amperes
B. ampere-hours
C. watts
D. watt-hours
Answer» C. watts
Discussion
39.

Each cell has a vent cap

A. to allow gases out when the cell is on charge
B. to add water to the cell if needed
C. to check the level of electrolyte
D. to do all above functions
Answer» E.
Discussion
40.

The specific gravity of electrolyte is measured by

A. manometer
B. a mechanical gauge
C. hydrometer
D. psychrometer
Answer» D. psychrometer
Discussion
41.

A constant-voltage generator has

A. minimum efficiency
B. minimum current capacity
C. low internal resistance
D. high internal resistance
Answer» D. high internal resistance
Discussion
42.

If a battery is wrongly connected on charge following will happen

A. current delivered by the battery will be high
B. current drawing will be nil
C. current drawing will be very small
D. current drawing will be very high
Answer» E.
Discussion
43.

When the load resistance equals the generator resistance which of the following will be maximum ?

A. Current
B. Efficiency of the circuit
C. Power in the load resistance
D. Voltage across the load resistance
Answer» D. Voltage across the load resistance
Discussion
44.

Cells are connected in series in order to

A. increase the voltage rating
B. increase the current rating
C. increase the life of the cells
D. none of the above
Answer» B. increase the current rating
Discussion
45.

Those substances of the cell which take active part in chemical combination and hence produce electricity during charging or discharging are known as______materials.

A. passive
B. active
C. redundant
D. inert
Answer» C. redundant
Discussion
46.

The charge required to liberate one gram equivalent of any substance is known as ______ constant

A. Time
B. Faraday’s
C. Boltzman
D. none of the above
Answer» C. Boltzman
Discussion
47.

In ______ system the charging current is intermittently controlled at either a maximum or minimum value

A. two rate charge control
B. trickle charge
C. floating charge
D. an equalizing charge
Answer» B. trickle charge
Discussion
48.

A battery of 6 cells will show a drop of _____ volts from fully charged state to fully discharged state.

A. 1.0
B. 1.5
C. 2.4
D. 2.9
Answer» D. 2.9
Discussion
49.

In constant-current charging method, the supply voltage from discharged to fully charged condition

A. decreases
B. increases
C. remains constant
D. none of the above
Answer» C. remains constant
Discussion
50.

In constant voltage charging method, the charging current from discharged to fully charged condition

A. decreases
B. increases
C. remains constant
D. none of the above
Answer» B. increases
Discussion