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Power as work done over time taken

Power $$(P)$$ is the energy generated per unit time.

Because energy is the ability to do work, power can also be defined as the work done per unit time.

A motor which uses a high power can do more work (or use more energy) in a fixed amount of time than a motor with a low power.

The power is given by: $$$\Tblue{\text{power}}=\frac{\Tred{\text{work done}}}{\Torange{\text{time taken}}}=\frac{\Tred{\text{energy generated}}}{\Torange{\text{time taken}}}$$$

The SI unit of power is the watt $$(\text{W})$$. One watt is equivalent to one joule per second (i.e. $$1\text{ W}=1\text{ J s}^{-1}$$).

A light bulb that does $$\Tred{500 \text{ J}}$$ of work in $$\Torange{5 \us}$$ has a power of $$\Tblue{100 \text{ W}}.$$

A microwave with a power of $$\Tblue{0.8 \text{ kW}} $$ delivers $$\Tred{16 \text{ kJ}}$$ of energy during a $$\Torange{20 \us} $$ period.

Coal is burnt in this power station to create electrical power for homes.
Coal is burnt in this power station to create electrical power for homes.