A student connects three lamps in a parallel circuit. Describe two differences between a parallel circuit and a series circuit, and explain why removing one lamp from the parallel circuit does not cause the other two lamps to go out.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
1. In a parallel circuit the current splits between the branches, whereas in a series circuit the same current flows through all components.
2. In a parallel circuit each lamp has the full supply voltage across it, whereas in a series circuit the supply voltage is divided between the lamps.
Removing one lamp only breaks the branch that lamp is on; the other branches remain connected to the supply, so current can still flow through the remaining lamps and they stay lit.
2. In a parallel circuit each lamp has the full supply voltage across it, whereas in a series circuit the supply voltage is divided between the lamps.
Removing one lamp only breaks the branch that lamp is on; the other branches remain connected to the supply, so current can still flow through the remaining lamps and they stay lit.
Examiner tips
- State the two differences clearly, using the terms "current splits" and "voltage is divided". Explain that each lamp is on its own branch and that breaking one branch does not affect the others.
Common mistakes
- Confusing voltage and current differences, or saying all lamps get the same current in a parallel circuit. Failing to mention that each lamp is on a separate branch, so removing one does not open the whole circuit.
Mark scheme (4 marks)
- Difference 1: In a parallel circuit the current splits/divides between branches, whereas in a series circuit the same current flows through all components.
- Difference 2: In a parallel circuit each component has the same voltage across it as the supply voltage, whereas in a series circuit the supply voltage is shared/split between components.
- Each lamp in a parallel circuit is on its own separate branch/loop connected directly to the supply.
- Removing one lamp only breaks that branch, so current can still flow through the other branches/lamps.
Key terms in this question
parallel circuit · series circuit
Related
- All Eduqas GCSE Physics revision notes →
- How to answer a "Describe" question →
- Decode the mark scheme abbreviations →
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