Pearson Edexcel International GCSE (9–1) · PHYSICS · Unit
Energy Resources and Energy Transfers
175 practice questions
Topics covered
Practice questions
81–90 of 90 · Normal
Question 81
5 marks · Normal
Answer and see the solution →A city is deciding between building a tidal power station and a new gas-fired power station.
(a)[2 marks]Describe the energy transfers that occur in generating electricity using a tidal scheme.
(b)[2 marks]State two disadvantages of tidal power stations.
(c)[1 mark]Explain one reason why a gas-fired power station can quickly respond to sudden demand, but a tidal power station cannot.
Question 82
7 marks · Normal
Answer and see the solution →The government of a country is deciding between building a geothermal power station and a gas-fired power station to supply electricity to a new city. The city is also encouraging the use of solar heating panels for domestic water heating.
(a)[2 marks]Describe the main energy transfers involved in generating electricity using geothermal energy.
(b)[2 marks]Explain one advantage and one disadvantage of using a gas-fired power station compared to geothermal power for the city.
(c)[3 marks]Explain how a solar heating panel works to heat water for a house.
Question 83
6 marks · Normal
Answer and see the solution →A large country currently relies mostly on coal-fired and hydroelectric power stations. It is considering increasing its use of wind turbines. The graph below shows a typical day's changes in national electricity demand.
Electricity demand (GW) throughout a day (a)[1 mark]At what time of day is electricity demand at its highest? Give your answer in hours.
(b)[2 marks]Which type of power station (coal-fired, hydroelectric, or wind turbine) is best suited to deal with sudden increases in demand shown on the graph? Explain your answer.
(c)[2 marks]Describe one environmental disadvantage of relying on coal-fired power stations and one disadvantage of relying on wind turbines.
(d)[1 mark]Suggest one reason why hydroelectric or wind power alone cannot always meet all the demand shown in the graph.
Question 84
7 marks · Normal
Answer and see the solution →A village uses two main sources for its electricity supply: a local river is used for hydroelectric power, and a diesel generator provides backup power when needed. Many houses also have solar heating panels for water heating.
(a)[2 marks]Describe the energy transfers that occur when generating electricity using the local hydroelectric power station.
(b)[1 mark]Give one environmental disadvantage of using the diesel generator.
(c)[1 mark]Suggest one reason why the diesel generator is only used as a backup and not as the main supplier.
(d)[3 marks]Explain how the design of a solar heating panel makes it efficient at heating water. Refer to specific features.
Question 85
5 marks · Normal
Answer and see the solution →A large electric motor is used to lift water from a well and also to pump the water through metal pipes. The table shows some of the energy transfers during one second of operation.
Process Energy transferred (J) Electrical energy supplied 1800 GPE gained by water 900 Heat energy to pipes 200 Sound energy 10 (a)[1 mark]State the physical quantity which is measured in joules (J).
(b)[2 marks]Calculate the efficiency of the motor in transferring electrical energy to useful energy. Give your answer as a percentage.
(c)[2 marks]Describe one way that unwanted energy transfer from the pipes could be reduced.
Question 86
6 marks · Normal
Answer and see the solution →The diagram shows a rectangular solar heating panel used to heat water for a home. Water enters the pipe at A and leaves at B after flowing through the panel. The inside of the panel is painted matt black and covered by a glass sheet.
Solar heating panel (not to scale) (a)[2 marks]Explain why the inside surface of the panel is painted matt black.
(b)[1 mark]Suggest one reason for covering the panel with a glass sheet.
(c)[2 marks]State and explain which energy transfer process is mainly responsible for transferring energy from the Sun to the panel.
(d)[1 mark]Describe how convection helps heat water inside the pipe.
Question 87
6 marks · Normal
Answer and see the solution →In a hydroelectric power station, water of mass 2.0 × 10^5 kg falls from a height of 50 m every minute to turn the turbines. The electrical power output of the station is 1.0 MW (1.0 × 10^6 W). Assume g = 10 N/kg.
(a)[2 marks]Calculate the total gravitational potential energy lost by the water each minute.
(b)[2 marks]How much electrical energy is produced by the station each minute?
(c)[2 marks]Calculate the efficiency of the power station.
Question 88
5 marks · Normal
Answer and see the solution →A metal saucepan is placed on a stove to heat water for cooking. The saucepan has a metal handle, but some are designed with a wooden covering on the handle.
(a)[2 marks]State and explain which process is mainly responsible for transferring thermal energy from the flame to the water.
(b)[2 marks]Explain why it is beneficial for the handle to have a wooden covering, using ideas about thermal conductivity.
(c)[1 mark]Give the correct SI unit for energy.
Question 89
6 marks · Normal
Answer and see the solution →A student of mass 45 kg runs up a staircase that is 3 meters high in 8 seconds.
(a)[2 marks]Calculate the change in gravitational potential energy (GPE) of the student.
(b)[3 marks]Calculate the average power generated by the student while running up the stairs.
(c)[1 mark]State the correct unit for power.
Question 90
5 marks · Normal
Answer and see the solution →A power station uses natural gas to generate electricity. Some of the energy from burning gas is used for useful work; some is wasted as heat.
(a)[1 mark]State the unit of power and give its symbol.
(b)[2 marks]The power station transfers 2.4 × 10^8 J of useful electrical energy every second. Calculate its useful power output. Give your answer in MW.
(c)[2 marks]Explain why the total energy output of the power station is more than just the useful energy output.