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GCSE Standard Questions: Electricity in the Home

Q21. An engineering company has invented pavement tiles that generate electricity as box people walk on them. The photo shows someone walking on the pavement tiles.

(a) Give the equation that links current (I), potential difference (V) and power (P)

[1 mark]

(b) When a person walks on a tile, a potential difference of 40 V is induced across the tile.

The power output of the tile is 4.4 W.

Calculate the current in the tile.

[3 marks]

(c) Give the equation links efficiency, total power input and useful power output.

[1 mark]

(d) The tiles are used to power LED lights in the pavement.

An LED light has a total power input of 4.0 W.

The efficiency of the LED light is 0.85

Calculate the useful power output of the LED light.

[3 marks]

(Total 8 marks)