Math Playground
Physics

Electric power

P = VI. How much energy a circuit eats per second.

Electric power is the rate of energy transfer in a circuit.

Try this
5
power P = V · I (mains voltage 230 V) = 1150 W
Electrical power

Watts = volts × amps. The three forms are interchangeable using Ohm's law V = IR.

Your turn

A kettle draws 9 A from a 230 V supply. What's its power?

Energy on your bill is power × time, in kilowatt-hours. A 2 kW kettle for 6 minutes (0.1 h) uses 0.2 kWh — a few pence.

Power