Edexcel IGCSE Physics 2.5 Electrical Energy Transfer: E = IVt

Practise calculating electrical energy, current, voltage or time for lamps, batteries and other circuit components.

Exam points

convert time to seconds before substituting current, voltage and time into E=IVt
rearrange E=IVt to isolate current, voltage or operating time
convert kJ to J and round the final value to the requested precision

[Maximum number: 3]

The diagram shows a domestic lighting circuit.

Figure for Question 2.5 Electrical energy transfer question 1 — Edexcel IGCSE Physics

When switch 1 is closed, the current in lamp 1 is 22 mA .

Calculate the energy transferred by lamp 1 when it is on for 30 seconds.

energy transferred = ............ J

Marking points:
- substitution into $P=\frac{E}{t}$
- rearrangement
- evaluation

Example:
$5=\frac{E}{30}$ $E=5\times30$ $E=150\ \mathrm{J}$

Accept:
- ECF from 7(b)(ii)
- $E=230\times22\times10^{-3}\times30$
- 151.8, 152, or $153\ \mathrm{J}$
- use of E=VIt or other valid methods

Marking guidance:
- Deduct 1 mark for power-of-ten error.

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2.5 Electrical energy transfer question 1