Lesson 4.7.3.4

4.7.3.4 Transformers (HT only) Quiz: AQA Physics, Unit 7

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 4.7.3.4, Transformers (HT only): 20 multiple choice questions for the AQA GCSE Physics (8463), Unit 7: Magnetism and electromagnetism, written with Revision Ninja.

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The 20 questions

  1. What core material is used in a basic transformer?

    • Plastic
    • Aluminium
    • Iron
    • Copper

  2. Which coil of a transformer is connected to the supply?

    • The core coil
    • The secondary coil
    • The output coil
    • The primary coil

  3. What type of current is required in the primary coil of a transformer?

    • Alternating current
    • Induced current
    • Direct voltage
    • Direct current

  4. Why is iron chosen as the core material in a transformer?

    • Poor conductor
    • Easily magnetised
    • High electrical resistance
    • High melting point

  5. In an ideal step-up transformer, how do the potential differences compare?

    • Vs greater than Vp
    • Vs less than Vp
    • Vs drops to zero
    • Vs equal to Vp

  6. Which feature distinguishes a step-down transformer?

    • Equal coil turns
    • More secondary turns
    • Fewer secondary turns
    • No iron core

  7. Which equation correctly links transformer turns and potential differences?

    • Vp + Vs = np + ns
    • Vp × Vs = np × ns
    • Vp / Vs = np / ns
    • Vp / np = Vs × ns

  8. For a 100% efficient transformer, what quantity remains constant?

    • Electrical power
    • Resistance
    • Current
    • Potential difference

  9. A transformer has 200 primary turns and 1000 secondary turns. The primary p.d. is 40 V. What is the secondary p.d.?

    • 1000 V
    • 200 V
    • 40 V
    • 8000 V

  10. A transformer has 500 primary turns, a 240 V supply and a 12 V output. How many secondary turns are there?

    • 25
    • 5
    • 2500
    • 250

  11. A 230 V primary supplies a 12 V secondary carrying 5 A (ideal transformer). What is the primary current?

    • 5.0 A
    • 0.52 A
    • 19 A
    • 0.26 A

  12. A transformer delivers 60 W of output power from a 240 V supply, with 100% efficiency. What current does the supply provide?

    • 2.5 A
    • 5 A
    • 0.05 A
    • 0.25 A

  13. A transformer changes 25 V to 250 V. What type of transformer is it?

    • Step-up
    • Isolation
    • Direct current
    • Step-down

  14. A step-up transformer raises 10 V to 100 V with a 3 A primary current. Assuming 100% efficiency, what is the secondary current?

    • 0.3 A
    • 300 A
    • 30 A
    • 3 A

  15. Why does a step-up transformer reduce the secondary current for constant power?

    • Higher p.d. gives lower current
    • Coils have fewer turns
    • Magnetic field weakens
    • Resistance drops to zero

  16. A primary coil has 100 turns and a 230 V supply. How many secondary turns give 11.5 V?

    • 50
    • 2300
    • 500
    • 5

  17. Why does the national grid use a high potential difference for power transmission?

    • Increases cable speed
    • Eliminates all resistance
    • Reduces thermal energy loss
    • Stops magnetic interference

  18. If transmission voltage increases from 25 kV to 250 kV for constant power, what happens to current?

    • Increases tenfold
    • Falls to one tenth
    • Drops to zero
    • Remains unchanged

  19. A transformer's secondary coil has four times as many turns as its primary. What is the ratio Vs/Vp?

    • 16
    • 1/4
    • 4
    • 2

  20. A transformer has 2000 primary turns and 100 secondary turns, with a 4000 V primary. What is the secondary p.d.?

    • 2 V
    • 200 V
    • 8000 V
    • 20 V

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