Lesson 4.3.1

4.3.1 Series and parallel circuits Quiz: OCR Physics, Unit 3

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 4.3.1, Series and parallel circuits: 20 multiple choice questions for the OCR Physics (H156), Unit 3: Electrons, waves and photons, written with Revision Ninja.

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The 20 questions

  1. Kirchhoff's second law is a consequence of which conservation law?

    • conservation of mass
    • conservation of momentum
    • conservation of energy
    • conservation of charge

  2. Kirchhoff's first law is based on the conservation of which physical quantity?

    • charge
    • momentum
    • energy
    • potential difference

  3. Two resistors of 3 ohm and 6 ohm are connected in series. What is the total resistance?

    • 2 ohm
    • 18 ohm
    • 9 ohm
    • 4.5 ohm

  4. A 6 ohm and a 3 ohm resistor are connected in parallel. What is the total resistance?

    • 0.5 ohm
    • 4.5 ohm
    • 9 ohm
    • 2 ohm

  5. Three 12 ohm resistors are connected in parallel. What is the total resistance?

    • 6.0 ohm
    • 36 ohm
    • 12 ohm
    • 4.0 ohm

  6. How does current compare across all components in a simple series circuit?

    • identical
    • divided equally
    • variable
    • inversely proportional

  7. How does potential difference across each parallel branch compare to total supply voltage?

    • double supply voltage
    • half supply voltage
    • equal to supply
    • divided by branches

  8. How does total resistance of parallel resistors compare to the smallest individual resistance?

    • equal
    • double
    • larger
    • smaller

  9. A 12 V supply is connected across a 4 ohm and an 8 ohm resistor in series. What is the p.d. across the 4 ohm resistor?

    • 3.0 V
    • 8.0 V
    • 12 V
    • 4.0 V

  10. A 2 ohm and a 6 ohm resistor are in parallel across a 6 V supply. What is the total current drawn from the supply?

    • 4 A
    • 0.75 A
    • 3 A
    • 1 A

  11. A 6 ohm and a 3 ohm resistor are in parallel across a 6 V supply. What current flows through the 6 ohm resistor?

    • 2.0 A
    • 0.5 A
    • 3.0 A
    • 1.0 A

  12. Two cells of e.m.f. 1.5 V each are connected in series, with internal resistance ignored. What is the total e.m.f.?

    • 2.25 V
    • 0.75 V
    • 3.0 V
    • 1.5 V

  13. A 9 V source drives current through a 2 ohm and a 1 ohm resistor in series. What is the p.d. across the 2 ohm resistor?

    • 3 V
    • 6 V
    • 9 V
    • 2 V

  14. A 4 ohm resistor is in series with a parallel combination of 6 ohm and 3 ohm. The supply is 12 V. What is the p.d. across the 4 ohm resistor?

    • 4 V
    • 6 V
    • 12 V
    • 8 V

  15. In the circuit of a 4 ohm resistor in series with (6 ohm parallel 3 ohm) on a 12 V supply, what is the current through the 3 ohm resistor?

    • 1.3 A
    • 2.0 A
    • 0.67 A
    • 4.0 A

  16. Adding a resistor in parallel to an existing circuit branch causes the total resistance to:

    • increase
    • stay the same
    • decrease
    • become infinite

  17. What happens to total circuit resistance when an identical resistor is added in parallel?

    • It stays constant
    • It decreases
    • It doubles
    • It increases

  18. Two resistors R1 and R2 are in parallel. What fraction of the total current flows through R1?

    • (R1 + R2)/R2
    • R2/(R1 + R2)
    • R1 R2/(R1 + R2)
    • R1/(R1 + R2)

  19. Two cells of e.m.f. 2 V and 4 V are connected in series opposing each other. What is the net e.m.f. around the loop?

    • 2 V
    • 4 V
    • 6 V
    • 8 V

  20. A loop contains e.m.f.s of 6 V and 2 V opposing each other with 4 ohm total resistance. What is the current?

    • 0.5 A
    • 4 A
    • 2 A
    • 1 A

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