Physics 5054 · O Level · Electrical current

Electrical current — practice question

Inside a car’s engine compartment, the battery delivers a current of 120 A to the starter motor.
(a)[2]

The starter motor is turned on for 3.5 s. Calculate the charge that flows through the starter motor in this time.

(b)[2]

A relay is used to switch the starter motor circuit on and off, and it is governed by a second circuit. The driver uses a switch in that second circuit to operate the relay and control whether the starter motor is on or off. Explain how the current in the second circuit controls the relay.

Worked solution & mark scheme

This 4-mark question has a full step-by-step worked solution and mark scheme. One marking point: Hence, $Q = It = 120 \times 3.5$

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