# A delivery driver notices that when two identical electric vehicles (EVs) are being charged in parallel from the same charging station, the charging station's total current is greater than when only one EV is being charged. The station's output voltage remains constant. Explain why connecting the two EVs in parallel increases the total current drawn from the charging station, and describe what happens to the total resistance of the circuit as more EVs are added in parallel.

> OCR A-Level Physics B: Advancing Physics (H557) — 3.5 Newton's laws and momentum · Explain · 5 marks

> Two identical electric vehicles are connected in parallel to a charging station. The potential difference supplied by the charging station remains constant at all times.

## Mark scheme (5 marks)

1. In a parallel circuit, each EV (component) has the same potential difference across it as the supply
2. Adding a second EV in parallel provides an additional path/branch for current to flow through
3. The total current drawn from the station increases because the total current equals the sum of the currents through each branch
4. The total resistance of the circuit decreases as more EVs are added in parallel
5. Because voltage is constant and resistance decreases, by V = IR the total current must increase (linking resistance decrease to current increase)

## Key terms

- [parallel](https://www.gradenine.co.uk/glossary/parallel)
- [total resistance](https://www.gradenine.co.uk/glossary/total-resistance)

## Related

- [Revision notes for OCR A-Level Physics B: Advancing Physics (H557)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/a-delivery-driver-notices-that-when-16cffc5a) · Published by Druglandscape Ltd.