Pearson Edexcel International GCSE (9–1) · PHYSICS · Chapter
Units (Electricity)
87 practice questions
Topics covered
Practice questions
11–20 of 43 · Normal
Question 11
1 mark · Normal
Answer and see the solution →Which of the following best describes the unit watt (W)?
- A.The energy transferred per coulomb of charge.
- B.The charge that passes a point every second.
- C.The energy transferred per second.
- D.The resistance to current flow in a circuit.
Question 12
3 marks · Normal
Answer and see the solution →A mains-powered oven uses a heating element with a high resistance. The oven has a power rating of 2000 W and is switched on for 15 minutes.
(a)[1 mark]State why the heating element must have a high resistance.
(b)[2 marks]Calculate the total energy transferred to the oven in this time.
Question 13
3 marks · Normal
Answer and see the solution →A student connects a thin filament lamp and a mains kettle in parallel to a 230 V supply. Both use the heating effect of current.
(a)[2 marks]Explain why the lamp glows but the kettle does not.
(b)[1 mark]State one use of the heating effect of electric current, other than in a lamp or a kettle.
Question 14
4 marks · Normal
Answer and see the solution →A washing machine has a power rating of 1800 W. It is used for 40 minutes during a wash cycle.
(a)[2 marks]Calculate the total energy transferred by the washing machine in one wash cycle.
(b)[2 marks]Suggest one effect on the wash cycle if the heating element had a much lower resistance than normal.
Question 15
3 marks · Normal
Answer and see the solution →Some electrical appliances have double insulation and do not need an earth wire.
(a)[1 mark]Describe what is meant by double insulation.
(b)[2 marks]Explain why double insulated appliances do not need an earth wire.
Question 16
4 marks · Normal
Answer and see the solution →A table lamp is rated at 60 W and is connected to a 240 V mains supply.
(a)[2 marks]Calculate the current in the lamp when it is operating at full power.
(b)[2 marks]Calculate the energy transferred if the lamp is left on for 30 minutes.
Question 17
1 mark · Normal
Answer and check →Which of the following best describes alternating current (a.c.) as opposed to direct current (d.c.)?
- A.A current that is always in the same direction and constant size.
- B.A current that regularly reverses direction and changes size with time.
- C.A current supplied only by batteries and cells.
- D.A current supplied only by power stations.
Question 18
3 marks · Normal
Answer and see the solution →A 24 V power supply powers a motor drawing a current of 1.5 A. The motor operates for 5 minutes. Calculate the total energy transferred to the motor.
Question 19
2 marks · Normal
Answer and see the solution →Describe two differences between the current from a cell and the current from the mains electricity supply.
Question 20
4 marks · Normal
Answer and see the solution →An electric heater has a power rating of 1.2 kW and operates from a 240 V supply.
(a)[2 marks]Calculate the current taken by the heater.
(b)[2 marks]Calculate the energy transferred by the heater in 10 minutes.