Pearson Edexcel International GCSE (9–1) · PHYSICS · Section
Supply and demand
16 practice questions
Practice questions
11–16 of 16
Question 11
4 marks · Normal
Answer and see the solution →The table shows the time it takes different types of power stations to start generating electricity after being turned on.
Type of power station Time to start generating (hours) Nuclear 12 Coal-fired 8 Oil-fired 4 Gas-fired 0.5 Hydroelectric 0.03 (a)[2 marks]Which power station is best for meeting a sudden, short-term increase in demand? Explain your answer.
(b)[2 marks]Suggest one reason why nuclear power stations are not used to meet sudden increases in demand.
Question 12
4 marks · Normal
Answer and see the solution →A power company is deciding how to best prepare for regular changes in electricity demand throughout each day.
(a)[1 mark]Describe one predictable change in electricity demand that occurs on most days.
(b)[1 mark]Suggest one way the company can plan to supply extra electricity during these predictable times.
(c)[2 marks]Explain why fossil fuel (coal, oil, or gas) power stations are often run continuously, even at night when demand is lower.
Question 13
2 marks · Normal
Answer and see the solution →Hydroelectric power stations are considered useful for balancing supply and demand in a national grid.
Describe two reasons why they are particularly effective for this purpose.
Question 14
3 marks · Normal
Answer and see the solution →A popular sport event ends on TV, and millions of people immediately turn on their electric kettles to make a drink.
Explain how electricity suppliers ensure that the extra demand can be met instantly. In your answer, refer to the types of power stations involved.
Question 15
3 marks · Normal
Answer and see the solution →Nuclear power stations are used to supply a large proportion of electricity in some countries.
Explain two reasons why nuclear power stations are not suitable for meeting sudden changes in electricity demand.
Question 16
4 marks · Normal
Answer and see the solution →Electricity demand is higher in winter than summer.
(a)[1 mark]State one reason why electricity demand is higher in winter.
(b)[3 marks]Explain how the national grid ensures there is enough electricity to supply everyone during periods of high demand.