Lesson T1.2.1

T1.2.1 Power ratings and energy use Quiz: KS3 Physics, Unit 1

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson T1.2.1, Power ratings and energy use: 20 multiple choice questions for the KS3 Physics (National Curriculum), Unit 1: Energy, written with Revision Ninja.

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The 20 questions

  1. What is the unit of power?

    • Newton (N)
    • Kilowatt-hour (kWh) per second
    • Joule (J)
    • Watt (W)

  2. What does a power rating of 2000 W mean?

    • The appliance has a mass of 2000 kg
    • 2000 J of energy is transferred every second
    • The appliance exerts a force of 2000 N
    • 2000 J of energy is transferred in total

  3. How many watts are in 1 kilowatt?

    • 100 W
    • 1000 W
    • 10 000 W
    • 10 W

  4. A 2 kW heater runs for 3 hours. How much energy is used?

    • 1.5 kWh
    • 5 kWh
    • 6 kWh
    • 0.67 kWh

  5. Which appliance has the highest power rating?

    • A 60 W light bulb used for lighting a room in the house
    • An 800 W microwave used for heating food for a short time
    • An electric oven rated 2200 W
    • A 25 W phone charger used overnight to charge a battery

  6. A 100 W bulb is left on for 10 hours. How much energy does it use?

    • 0.1 kWh
    • 1 kWh
    • 100 kWh
    • 10 kWh

  7. Energy transferred can be calculated using which formula?

    • Mass × speed
    • Force × area
    • Power × time
    • Power ÷ time

  8. Which unit is the kilowatt-hour a unit of?

    • Force
    • Energy
    • Power
    • Electric charge

  9. A 3 kW kettle runs for 30 minutes. How much energy does it use?

    • 0.17 kWh
    • 3.5 kWh
    • 6 kWh
    • 1.5 kWh

  10. How many joules are in 1 kWh?

    • 3600 J, which is the energy of 1 W running for one hour
    • 1000 J, which is the energy of 1 kW running for one second
    • 3 600 000 J (3.6 MJ)
    • 36 000 J, which is the energy of 10 W running for one hour

  11. A 1 kW heater runs for 2 hours and a 2 kW heater runs for 1 hour. What is the total energy used?

    • 3 kWh
    • 4 kWh
    • 2 kWh
    • 6 kWh

  12. Which appliance uses more energy in one hour?

    • A 1500 W hair dryer
    • They use the same energy
    • A 300 W fan
    • You cannot compare them

  13. A 60 W bulb is replaced by a 9 W LED giving the same light. Which statement is true?

    • The bulb and LED use the same energy per second, but the LED lasts longer in use
    • The LED uses less energy per second for the same light output
    • The LED transfers energy faster than the bulb, so it heats the room more quickly
    • The LED produces more light by using more energy than the bulb uses each second

  14. A microwave is rated 800 W. How many joules does it transfer in 10 seconds?

    • 8000 J
    • 800 J
    • 80 J
    • 80 000 J

  15. Power is best described as:

    • The rate of transfer of energy
    • The amount of mass in a system
    • The force applied to an object
    • The total energy stored in a store

  16. A 2.5 kW kettle boils water in 3 minutes. How much energy is transferred?

    • 450 kJ
    • 4.5 MJ
    • 7.5 kJ
    • 125 kJ

  17. A 1200 W appliance is used for 5 minutes. How much energy does it transfer?

    • 240 kJ
    • 360 kJ
    • 36 kJ
    • 4 kJ

  18. Which uses the most energy in one day: a 2 kW heater on for 4 hours or a 500 W computer on for 12 hours?

    • Neither uses any energy
    • The 2 kW heater, using 8 kWh
    • The 500 W computer, using 12 kWh
    • They use the same energy

  19. A 1500 W appliance uses 3 kWh of energy. For how long was it switched on?

    • 4.5 hours
    • 0.5 hours
    • 2 hours
    • 1.5 hours

  20. Why does a higher power rating mean an appliance transfers energy faster?

    • It has a greater mass
    • It uses a smaller force
    • It transfers energy over longer periods
    • More energy is transferred each second

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