Appliances transfer electrical energy to useful energy. For example, a fan transfers electrical energy to kinetic energy of the fan and an oven converts electrical energy to thermal energy to heat up your food.

The amount of energy transferred in an appliance can be calculated using the following equation:

• $E$= energy in joules (J)
• $P$= power in watts (W)
• $t$= time in seconds (s)

This equation tells us that more energy is transferred if the appliance has a higher power rating or if it is switched on for a longer time.