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.

51.

Weston standard cell at 20°C has voltage of ____ volts.

A. 0.8
B. 0.9
C. 1.0187
D. 1.5
Answer» D. 1.5
52.

Sulphated cells are indicated by

A. the loss of capacity of the cell
B. the decrease of the specific gravity
C. the low voltage of the cell on discharge
D. all above conditions
Answer» E.
53.

If a lead-acid cell is discharged below 1.8 V the following will happen.

A. Capacity of cell will reduce
B. Sulphation of plates will occur
C. Internal resistance will increase
D. All above will occur
Answer» E.
54.

The substances which combine together to store electrical energy during the charge are called ______ materials

A. active
B. passive
C. inert
D. dielectric
Answer» B. passive
55.

The common impurity in the electrolyte of lead-acid battery is

A. chlorine
B. dust particles
C. lead crystals
D. iron
Answer» E.
56.

In alkaline cell the electrolyte is

A. dilute sulphuric acid
B. concentrated sulphuric acid
C. NaOH
D. kOH
Answer» E.
57.

Dry cell is modification of

A. Deniell cell
B. Leclanche cell
C. Lead-acid cell
D. Edison cell
Answer» C. Lead-acid cell
58.

As compared to a lead-acid cell, the efficiency of a nickel-iron cell is less due to its

A. compactness
B. lower e.m.f.
C. small quantity of electrolyte used
D. higher internal resistance
Answer» E.
59.

During the idle period of the battery, strong electrolyte tends to change the active material of the cell into

A. Pb02
B. PbSC-4
C. PbO
D. Pb
Answer» C. PbO
60.

Charging a sulphated battery at high rate results in

A. boiling of electrolyte due to gassing
B. warping of plates
C. damage to separators, cell caps covers and battery case due to excessive temperature
D. all above
Answer» E.
61.

Five 2 V cells are connected in parallel. The output voltage is

A. 1 V
B. 1.5 V
C. 1.75 V
D. 2 V
Answer» E.
62.

Negative plate of an Edison cell is made of

A. copper
B. lead
C. iron
D. silver oxide
Answer» D. silver oxide
63.

Following will happen if battery charging rate is too high

A. excessive gassing will occur
B. temperature rise will occur
C. bulging and buckling of plates will occur
D. all above will occur
Answer» E.
64.

Mercury cell has which of the following characteristics?

A. Flat discharge current-voltage curve
B. High power to weight ratio
C. Comparatively longer shelf life under adverse conditions of high temperature and humidity
D. All of the above
Answer» E.
65.

As compared to constant-current system, the constant-voltage system of charging a lead acid cell has the advantage of

A. reducing time of charging
B. increasing cell capacity
C. both (A) and (B)
D. avoiding excessive gassing
Answer» D. avoiding excessive gassing
66.

_______ of electrolyte indicates the state of charge of the battery

A. colour
B. mass
C. viscosity
D. specific gravity
Answer» E.
67.

Excessive charging a battery tends to

A. produce gassing
B. increase the internal resistance of the battery
C. to corrode the positive plates into lead peroxide thereby weakening them physically
D. bring about all above changes
Answer» E.
68.

The active material of the positive plates of silver-zinc batteries is

A. silver oxide
B. lead oxide
C. lead
D. zinc powder
Answer» B. lead oxide
69.

Batteries are charged by

A. rectifiers
B. engine generator sets
C. motor generator sets
D. any one of the above methods
Answer» E.
70.

On overcharging a battery

A. It will bring about chemical change in active materials
B. It will increase the capacity of the battery
C. It will raise the specific gravity of the electrolyte
D. None of the above will occur
Answer» E.
71.

Cells are connected in parallel to

A. Increase the efficiency
B. Increase the current capacity
C. Increase the voltage output
D. Increase the internal resistance
Answer» C. Increase the voltage output
72.

Electrolyte used in a lead-acid cell is

A. NaOH
B. only H₂SO₄
C. only water
D. dilute H₂SO₄
Answer» E.
73.

The ratio of ampere-hour efficiency to watt-hour efficiency of a lead-acid cell is

A. just one
B. always greater than one
C. always less than one
D. none of the above
Answer» C. always less than one
74.

While preparing electrolyte for a lead-acid battery

A. water is poured into acid
B. acid is poured into water
C. anyone of the two can be added to other chemical
D. none of the above
Answer» C. anyone of the two can be added to other chemical
75.

During charging the specific gravity of the electrolyte of a lead-acid battery

A. increases
B. decreases
C. remains the same
D. becomes zero
Answer» B. decreases
76.

Electrolyte used in a lead-acid cell is%!

A. NaOH
B. only H‚ÇÇSO‚ÇÑ
C. only water
D. dilute H‚ÇÇSO‚ÇÑ
Answer» E.
77.

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
78.

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
79.

A dead storage battery can be revived by%!

A. adding distilled water
B. adding so-called battery restorer
C. a dose of H‚ÇÇSO‚ÇÑ
D. none of the above
Answer» E.
80.

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.
81.

The specific gravity of electrolyte is measured by%!

A. manometer
B. a mechanical gauge
C. hydrometer
D. psychrometer
Answer» D. psychrometer
82.

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
83.

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
84.

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.
85.

*$_Sulphated cells are indicated by?

A. the loss of capacity of the cell
B. the decrease of the specific gravity
C. the low voltage of the cell on discharge
D. all above conditions
Answer» E.
86.

*$_Electrolyte used in a lead-acid cell is?

A. NaOH
B. only H‚ÇÇSO‚ÇÑ
C. only water
D. dilute H‚ÇÇSO‚ÇÑ
Answer» E.
87.

*/*_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
88.

*/*_Negative plate of an Edison cell is made of?

A. copper
B. lead
C. iron
D. silver oxide
Answer» D. silver oxide
89.

*/*_During the idle period of the battery, strong electrolyte tends to change the active material of the cell into?

A. Pb02
B. PbSC-4
C. PbO
D. Pb
Answer» C. PbO
90.

*/*_As compared to constant-current system, the constant-voltage system of charging a lead acid cell has the advantage of?

A. reducing time of charging
B. increasing cell capacity
C. both (A) and (B)
D. avoiding excessive gassing
Answer» D. avoiding excessive gassing
91.

*/*_The active material of the positive plates of silver-zinc batteries is?

A. silver oxide
B. lead oxide
C. lead
D. zinc powder
Answer» B. lead oxide
92.

*/*_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%
93.

*/*_In alkaline cell the electrolyte is?

A. dilute sulphuric acid
B. concentrated sulphuric acid
C. NaOH
D. kOH
Answer» E.
94.

*/*_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.
95.

*/*_Chargmg of sulphated battery produces ____ heat.?

A. no
B. very little
C. less
D. more
Answer» E.
96.

*/*_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
97.

*/*_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.
98.

*/*_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
99.

*/*_The ratio of ampere-hour efficiency to watt-hour efficiency of a lead-acid cell is?

A. just one
B. always greater than one
C. always less than one
D. none of the above
Answer» C. always less than one
100.

%_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