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GCSE Questions: Energy Sources

Q27.

(a) During one year, 1.25 × 1018 J of energy was transferred from the National Grid.

Given that the number of seconds in 1 year = 3.16 × 107 calculate the mean power transfer from the National Grid.

Give your answer to 3 significant figures.

[4 marks]

(b) The diagram shows a house with a solar power system.

The solar cells generate electricity.

When the electricity generated by the solar cells is not needed, the energy is stored in a large battery.

(i) The charge flow through the cable between the solar cells and the battery in 24 hours box was 27 000 coulombs. Calculate the mean current in the cable.

[4 marks]

(ii) At one time, the total power input to the solar cells was 7.8 kW.

The efficiency of the solar cells was 15%

Calculate the useful power output of the solar cells.

[3 marks]

(c) It is unlikely that all of the electricity that the UK needs can be generated by solar power systems. Explain why.

[2 marks]

(Total 13 marks)