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GCSE Standard Questions: Electricity in the Home

Q10. The lighting in a home may be provided by LED bulbs, filament bulbs or halogen bulbs.

(a)

(i) In the box below, draw the circuit symbol for an LED.

[1 mark]

(ii) The graph shows how the power output from one type of LED varies with the potential difference across the LED.

The LED is connected in series with a battery and resistor.

The potential difference across the LED is 2.0 V.

Use data from the graph to calculate the energy transferred by the LED in 5 minutes.

[6 marks]

(b) The resistance of a filament bulb increases as the temperature of the filament increases.

Explain, in terms of the electrons and ions inside the filament, why the resistance increases.

[2 marks]

(c) Why are LED bulbs cheaper to use than filament bulbs or halogen bulbs that produce
the same brightness of light?

[1 mark]

(Total 10 marks)