A set of lights consists of 20 lamps connected in series to the 230 V mains electricity supply.

When the lights are switched on and working correctly, the current through each lamp is 0.25 A.

(a) (i) What is the total current drawn from the mains supply?

(1 mark)

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(a) (ii) Use an appropriate equation to calculate the charge passing through one of the lamps in 5 minutes.

Show clearly how you work out your answer and give the unit.

Total charge = ...................................
(3 marks)

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(b) One of the lamps in the set is a fuse lamp. This contains a filament which melts if a fault occurs. A short time after the lights are switched on, a fault causes the filament inside the fuse lamp to melt and all the lamps go out.

The householder cannot find another fuse lamp so connects a piece of aluminium foil across the contacts inside the fuse lamp holder.

When switched on, the nineteen remaining lamps work.

What the householder has done is dangerous.

Explain why.

(2 marks)

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From Q6 P2 AQA January 2011 (Higher)