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

Related Physics GCSE answers

All answers ▸

Why would the National Grid limit the amount of fossil fuels we combust at peak times of energy demand?


A wave with a constant velocity doubles its frequency. What happens to the wavelength?


Which renewable energy methods are the best?


Identify which of the following would be the most appropriate choice of fuse for a 1200W kettle operating on UK mains electricity (230V). A) 3A Fuse B) 5A Fuse C) 10A Fuse D) 13A Fuse