Electrical Appliances | GCSE Physics | Doodle Science
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Doodle Science teaches you high school physics in a less boring way in almost no time!
Script:
The amount of electrical energy transferred to an appliance depends on its power and the length of time it is switched on. The amount of mains electrical energy transferred is measured in kilowatt-hours. One unit is 1 kWh. The formula used to calculate this is E=P x t, where E is the energy transferred in kilowatt-hours, P is the power in kilowatts and T is the time in hours. For example, a 2kW electrical fire is switched on for 5 hours. It uses
(2 x 5=) 10kWh of electrical energy. You can also use the equation E=P x t when E is the energy transferred in Joules, P is the power in Watts and T is the time in seconds. For example a 20W lamp lit for 200 seconds transfers (20*200 =) 4000J of electrical energy.
Electricity meters measure the number of units of electricity used in a building. The more units used the greater the cost. For example, if 5 units of electricity are used at a cost of 8p per unit, the total cost will be (5 x 8=) 40p.