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Questions on Electric Circuits

Q10. In the circuit above, both the bulbs light up. Suddenly they both go out. The two bulbs are tested. Bulb A works but bulb B is broken.

(a) Bulb A was not broken but it went out. Why did it go out?

Bulbs A and B are in series. The break in the filament of bulb B serves as a break in the circuit. You need a complete conducting loop for a current to flow. The break means than no current flows so the lamp A goes out too.

1 mark

In the circuit below, only bulb B is broken.

(b)

(i) Does bulb A light up? Yes

1 mark

(ii) Does bulb C light up? Yes

1 mark

Maximum 3 marks