Explain the difference between energy and power.
Power is the rate at which energy is transferred. For example, a typical kettle may use 1.2 kiloWatts (kW) for about 2 minutes to boil water. This means that the kettle uses 1200 Joules of energy per second (Js-1) for 120 seconds. We can work out the total energy this takes using the equation:Power = Energy / TimeRearranging for energy gives us:Energy = Power × TimeSo:Energy = 1200Js-1 × 120s= 144,000JSo, in this example, a kettle requires 1200 Watts of power for 2 minutes to boil the water, or 144,000 Joules of energy in total.
HJ
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