• Students should be able to explain how the power transfer in any circuit device is related to the potential difference across it and the current through it, and to the energy changes over time:

power = potential difference × current


power = current 2 × resistance

P = I2 R

power, P, in watts, W

potential difference, V, in volts, V

current, I, in amperes, A (amp is acceptable for ampere) resistance, R, in ohms, Ω

WS 4.5 - Interconvert units.

MS 3b Change the subject of an equation

MS 3c Substitute numerical values into algebraic equations using appropriate units for physical quantities

KS4 -P5.3 - Electrical power and potential difference


Foundation Answers


Higher answers