NECO 2001 Physics · Question 40

A lead-acid accumulator is used in preference to a dry battery in a car because

Options

A.a dry battery cannot supply the necessary high voltage
B.a dry battery would not operate on a cold frosty morning
C.the accumulator can give a bigger current and can be recharged
D.the accumulator can supply a.c
E.the chemicals used in a dry battery constitute a fire hazard.

Answer: C. the accumulator can give a bigger current and can be recharged

Explanation written with AI and checked against the answer key

Analyze the question: We need the reason a car uses a lead-acid accumulator instead of a dry cell (such as a Leclanché cell).

Concept:

A dry cell is a primary cell. It has a high internal resistance, so it can only supply small currents, and it cannot be recharged effectively.
A lead-acid accumulator is a secondary cell. It has a very low internal resistance, so it can deliver a very large current for a short time. This is what the car's starter motor needs. It can also be recharged by the car's alternator or dynamo while the engine runs.

Checking each option:

A. Wrong. A dry cell gives about 1.5 V, but you can connect cells in series to get 12 V. Voltage is not the main reason.
B. Wrong. Cold weather reduces the output of any chemical cell, including the accumulator, so this is not a real distinction.
C. Correct. The accumulator can give a large current (to crank the starter motor) and it is rechargeable.
D. Wrong. Both produce direct current (d.c.), not a.c.
E. Wrong. Dry cells are not a notable fire hazard.

Answer: The accumulator's low internal resistance lets it supply the high starting current, and it can be recharged.

Tip: For "accumulator vs dry cell" questions, remember "Big current + Rechargeable". Accumulator = secondary cell, low internal resistance. Dry cell = primary cell, high internal resistance, not rechargeable.

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