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.

101.

%_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
102.

%_Ampere hour capacity of an industrial battery is based on ____ hours discharge rate._%

A. 8
B. 12
C. 16
D. 24
Answer» B. 12
103.

%_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
104.

%_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
105.

%_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
106.

%_Specific gravity of electrolyte in Edison cell is_%

A. 0.8
B. 0.95
C. 1.1
D. 1.21
Answer» E.
107.

_ 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.
108.

_ 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
109.

_ 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
110.

_ 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.
111.

__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.
112.

_________ of electrolyte indicates the state of charge of the battery__

A. colour
B. mass
C. viscosity
D. specific gravity
Answer» E.
113.

__Batteries are charged by__

A. rectifiers
B. engine generator sets
C. motor generator sets
D. any one of the above methods
Answer» E.
114.

__The capacity of a lead-acid cell is measured in__

A. amperes
B. ampere-hours
C. watts
D. watt-hours
Answer» C. watts
115.

__Dry cell is modification of__

A. Deniell cell
B. Leclanche cell
C. Lead-acid cell
D. Edison cell
Answer» C. Lead-acid cell
116.

__The effect of sulphation is that the internal resistance__

A. increases
B. decreases
C. remains same
D. none of the above
Answer» B. decreases
117.

__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 H‚ÇÇSO‚ÇÑ decreases
Answer» B. it gives out energy
118.

__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.
119.

__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.
120.

__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
121.

__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
122.

__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
123.

__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
124.

__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.
125.

__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
126.

__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
127.

__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
128.

_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
129.

_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
130.

_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.
131.

_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.
132.

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.
133.

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.
134.

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.
135.

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.
136.

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.
137.

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.
138.

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.
139.

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

A. 500
B. 700
C. 1000
D. 1250
Answer» E.
140.

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
141.

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.
142.

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
143.

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

A. 2%
B. 4%
C. 6%
D. 8%
Answer» E.
144.

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
145.

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

A. one part H2O, three parts H‚ÇÇSO‚ÇÑ
B. two parts H2O, two parts H‚ÇÇSO‚ÇÑ
C. three parts H2O, one part H‚ÇÇSO‚ÇÑ
D. all H‚ÇÇSO‚ÇÑ
Answer» D. all H‚Äö√á√áSO‚Äö√á√ë
146.

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

A. glass
B. plastic
C. wood
D. all above
Answer» E.
147.

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
148.

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
149.

Which of the following primary cells has the lowest voltage ?$?

A. Lithium
B. Zinc-chloride
C. Mercury
D. Carbon-zinc
Answer» D. Carbon-zinc
150.

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