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GCSE Questions: Energy Sources

Q21. Here is a hydroelectric power station.

(a) Electricity is generated when water from the reservoir flows through the turbines.

(i) Write down the equation which links density (ρ), mass (m) and volume (V).

[1 mark]

(ii) The reservoir stores 6,500,000 m3 of water.

The density of the water is 998 kg/m3 .

Calculate the mass of water in the reservoir. (Give your answer in standard form).

[4 marks]

(iii) Write down the equation which links energy transferred (E), power (P) and time (t).

[1 mark]

(iv) The electrical generators can provide 1.5 × 109 W of power for a maximum of 5 hours.

Calculate the maximum energy that can be transferred by the electrical generators.

[3 marks]

(b) The graph below shows how the UK demand for electricity increases and decreases during one day.

The hydroelectric power station in the diagram above can provide 1.5 × 109 W of power for a maximum of 5 hours.

Give two reasons why this hydroelectric power station is not able to meet the increase in demand shown between 04:00 and 16:00 in this graph.

[2 marks]

(Total 11 marks)