Definition of power

Power is defined as the rate at which work is done, or energy is delivered:

Two related but distinct quantities are used depending on the situation:

• Average power, $P_{av}$, is the ratio of the total work done to the total time taken over some interval: $P_{av} = \dfrac{\text{total work done}}{\text{total time taken}}$. This is useful when only the overall work and overall duration are known (e.g. a fan's total electrical energy consumption over a month). …