Many of the electrical appliances used at home transfer electrical energy into different forms of energy. The energy that a machine uses each second is called its power. All appliances have a power rating in watts (W) or kilowatts (kW). The higher the power of the appliance, the more energy it uses. The amount of energy used by an appliance depends on its power and the time the appliance works for.
Electricity at home is sold by the kilowatt-hour. This is the energy used by a device running at 1000 W for 1 hour. The table below shows various electrical appliances and their power ratings.
|Appliance||Power Rating (W)|
|Electric cooker hob (one ring)||2000|
|Electric cooker oven||1500-2500|
|Energy efficient light bulb||15|
|Charging mobile phone||3|