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Questions on Electric Circuits

Q14. Gary uses the following circuit to operate the electric motor of his model crane. Look carefully at the way Gary has connected the two cells.

When he closes switch A the motor runs and the crane lifts a load.

(a) Gary opens switch A and closes switch B. Describe what happens to the motor.

1 mark

(b) Gary closes both switches, A and B. Describe what happens to the motor.

1 mark

(c) Both switches should not be closed at the same time. Explain why.

1 mark

(d) Gary puts a resistor into his circuit as shown.

What difference does the resistor make to the motor:

(i) when switch A is closed and switch B is open?

1 mark

(ii) when switch A is open and switch B is closed?

1 mark

Maximum 5 marks