# Automobile Engineering Questions and Answers – Storage Batteries

This set of Automobile Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Storage Batteries”.

1. What is the colour of a positive plate of a lead-acid battery?
a) White
b) Grey
c) White
d) Brown

Explanation: A positive plate of a lead-acid battery is brown in colour. A negative plate of a lead-acid battery is grey in colour. For each plate, there is a supporting grid made of an alloy of lead and antimony.

2. What gets deposited on the plates of a discharged lead-acid battery?
a) PbO2
b) Pb2O4
c) Pb
d) PbSO4

Explanation: PbSO4 gets deposited on the plates of a discharged lead-acid battery. During discharging the reaction happens in the right direction. PbSO4 gets deposited on both negative and positive plates.

3. What is the twenty-minute rating of battery?
a) Rate of current for 20 minutes with a minimum cell voltage of 1.5 V
b) Time for which the battery can supply 25 A at 80℉ with minimum cell voltage 1.75 V
c) The current which the battery can supply continuously for 30 seconds with minimum cell voltage 1.2 V
d) Lasting power of a battery on a small load

Explanation: The rate of current 20 minutes with a minimum cell voltage of 1.5 V is called a twenty-minute rating of the battery. The temperature of the battery at the start of the test is brought to 80℉. It represents the rate of current a battery can deliver continuously.

4. What is the reserve capacity of battery?
a) Time for which the battery can supply 25 A at 80℉ with minimum cell voltage 1.75 V
b) The current which the battery can supply continuously for 30 seconds with minimum cell voltage 1.2 V
c) Lasting power of a battery on a small load
d) Rate of current for 20 minutes with a minimum cell voltage of 1.5 V

Explanation: The reserve capacity is the time for which the battery can supply 25 A at 80℉ with minimum cell voltage 1.75 V. It is the measurement for the total capacity of the battery.

5. What is the cold rate of a battery?
a) Lasting power of a battery on a small load
b) Rate of current for 20 minutes with a minimum cell voltage of 1.5 V
c) The current which the battery can supply continuously for 30 seconds with minimum cell voltage 1.2 V
d) Time for which the battery can supply 25 A at 80℉ with minimum cell voltage 1.75 V

Explanation: It is a measure of the worst conditions under which a battery is expected to deliver current, e.g., during starting the engine and operating under extreme cold. The cold rate of a battery is the current which the battery can supply continuously for 30 seconds with minimum cell voltage 1.2 V.

6. What is a twenty-hour rate of a battery?
a) The current which the battery can supply continuously for 30 seconds with minimum cell voltage 1.2 V
b) Lasting power of a battery on a small load
c) Time for which the battery can supply 25 A at 80℉ with minimum cell voltage 1.75 V
d) Rate of current for 20 minutes with a minimum cell voltage of 1.5 V

Explanation: A twenty-hour rate of a battery is the lasting power of a battery on a small load. During this test, the temperature should be about 80oF. This rating is important for powering accessories when the engine is not running.

7. What should a fully-charged 6 cell automotive battery indicate?
a) 12 V
b) 12.6 V
c) The specific gravity of 1.29 at 32℃
d) 12.6 V and the specific gravity of 1.29 at 32℃

Explanation: A fully-charged 6 cell automotive battery indicates 12.6 V and a specific gravity of 1.29 at 32℃. There should be no leak. The battery can be checked using a digital multimeter.

8. What is the number of positive plates in a battery cell?
a) One more than the negative plates
b) Two less than the negative plates
c) One less than the negative plates
d) Two more than the negative plates

Explanation: The number of positive plates in a battery cell is one less than the negative plates. One positive and one negative group of plates are sliding over each other, with separators sandwiched between them.

9. What is a maintenance-free battery?
a) A battery having lead-antimony plate grid
b) A battery having lead-calcium plate grid
c) A battery does not contain acid
d) A battery does not contain water

Explanation: A maintenance-free battery is a battery having a lead-calcium plate grid. The battery which uses this plate grid loses water very slowly.

10. Which of the following is the advantage of alkaline battery?
a) High energy density
b) Good discharge characteristics over a wide range of temperature
c) The specific gravity of electrolyte remains the same
d) Cheap raw materials are used

Explanation: The advantage of the alkaline battery is that the specific gravity of electrolyte remains the same. The electrolyte does not take part in chemical reactions on charging or discharging.

Sanfoundry Global Education & Learning Series – Automobile Engineering.

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