GCSE Physics

kilo-watt example

Transfer of energy can mean many things - from electrical energy in a circuit, to work done repeatedly carrying bricks up a ladder. Let's see an example.

An electrical heater uses 450,000 J in 5 minutes. What is its power output?

Time must be in seconds, so 5 minutes = 300 seconds.
power = 450000 / 300 = 1500 W
Of course, we could write this answer as 1·5 kW.

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