Power

Power is defined as:

$P = \frac{E}{t} = \frac{W}{t}$

where $E$ or $W$ is the energy transferred or work done (J) and $t$ is the time (s).

Electrical power: $P = IV = I^2R = V^2/R$.

One watt (1 W) is one joule per second. Common multiples: 1 kW = 1000 W; 1 MW = $10^6$ W.

A higher power means energy is transferred more quickly. A 100 W light bulb transfers energy five times faster than a 20 W bulb.