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Pearson Edexcel International GCSE (9–1) · PHYSICS · Chapter

Units (Electricity)

87 practice questions

Start practising (87 questions)

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Practice questions

21–30 of 87

  1. Question 21

    2 marks · Easy

    An electric heater is labelled 500 W. How much energy does it transfer in 8 seconds?

    Answer and see the solution →

  2. Question 22

    2 marks · Easy

    Explain why the wires inside an electric oven are designed to have high resistance.

    Answer and see the solution →

  3. Question 23

    1 mark · Easy

    Which statement best describes why a 100 W bulb is brighter than a 40 W bulb?

    1. A.It transfers more energy every second.
    2. B.It uses less current.
    3. C.It is bigger in size.
    4. D.It has a higher resistance.
    Answer and check →

  4. Question 24

    4 marks · Normal

    A hairdryer uses the heating effect of an electric current. The label on the hairdryer states 'Power: 1200 W'.

    (a)

    Explain how the heating effect of current is used in a hairdryer.

    [2 marks]
    (b)

    Calculate the energy transferred by the hairdryer in 5 minutes of use.

    [2 marks]
    Answer and see the solution →

  5. Question 25

    3 marks · Normal

    Two halogen bulbs are labelled 50 W and 70 W. Both are in use for 20 seconds. The bulbs convert electrical energy into heat and light.

    Energy transferred in 20 seconds
    BulbPower (W)Time (s)Energy (J)
    A5020
    B7020
    (a)

    Calculate the energy transferred by bulb A in 20 seconds.

    [1 mark]
    (b)

    Calculate the energy transferred by bulb B in 20 seconds.

    [1 mark]
    (c)

    Explain why bulb B is brighter than bulb A.

    [1 mark]
    Answer and see the solution →

  6. Question 26

    3 marks · Normal

    Look at these two electrical appliances:

    ApplianceWire materialWire resistance
    ToasterNichrome (metal alloy)High
    Mains cable in wallCopperLow
    (a)

    Explain why the heating element in a toaster uses a wire with high resistance, but the wires in a mains cable use low resistance copper.

    [3 marks]
    Answer and see the solution →

  7. Question 27

    1 mark · Normal

    Which of the following best describes the unit watt (W)?

    1. A.The energy transferred per coulomb of charge.
    2. B.The charge that passes a point every second.
    3. C.The energy transferred per second.
    4. D.The resistance to current flow in a circuit.
    Answer and see the solution →

  8. Question 28

    3 marks · Normal

    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)

    State why the heating element must have a high resistance.

    [1 mark]
    (b)

    Calculate the total energy transferred to the oven in this time.

    [2 marks]
    Answer and see the solution →

  9. Question 29

    3 marks · Normal

    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)

    Explain why the lamp glows but the kettle does not.

    [2 marks]
    (b)

    State one use of the heating effect of electric current, other than in a lamp or a kettle.

    [1 mark]
    Answer and see the solution →

  10. Question 30

    4 marks · Normal

    A washing machine has a power rating of 1800 W. It is used for 40 minutes during a wash cycle.

    (a)

    Calculate the total energy transferred by the washing machine in one wash cycle.

    [2 marks]
    (b)

    Suggest one effect on the wash cycle if the heating element had a much lower resistance than normal.

    [2 marks]
    Answer and see the solution →