Electrical power

Electrical power

The power of an electrical appliance is given as \(\text{power}\times\text{potential difference}\times\text{current}\). This can be written as \(P = VI\) where:
- \(P\) is the power of the appliance in W
- \(V\) the potential difference across it in V
- \(I\) is the current through it in A
This can be combined with the resistance equation: \(\text{power}=\text{(current)}^2 \times\text{resistance}\) or \(P=I^2R\) where \(R\) is the resistance of the appliance in Ohms, Ω.
Most household appliances have a power rating, which can be used to determine the current that should flow through it from mains electricity.

Sign up to unlock the rest of this topic — plus every other topic, video, flashcard set and eBook guide in your SnapRevise+ subscription.

Cancel anytime — instant access the moment you sign up.