Power

Different devices transform or transfer energy at different rates Different devices transform or transfer energy at different rates. The rate is given by the equation power (watts, W) = If power is P, the energy transferred or transformed is E and the time taken for the energy transfer is t, then P =

A compact fluorescent light bulb transforms 64 800 J every hour A compact fluorescent light bulb transforms 64 800 J every hour. What is its power? Using: P = P = 64 800/(60 × 60) = 18 W

The power of a device can also be calculated using the equation: power = current × potential difference (watts, W) (amperes, A) (volts, V) When power is P, current is I and the potential difference provided by the supply is V, then P = I × V

This bread maker has a power rating of 600 W This bread maker has a power rating of 600 W. What size fuse should be fitted to the plug? Using: P = I × V Mains supply is 230 V. I = P / V = 600 W / 230 V = 2.6 A A 3 A fuse should be fitted.