You may have noticed on the labels of the appliances or fixtures we purchased that there is a label specifying: 100 (Watt), 500 W, 1000 W etc. But what does this information mean anyway?

We saw in mechanics the concept of power: energy / time. The electrical energy that is converted into these devices for various purposes and uses, such as generating motion (motors), generating heat (resistors), generating light energy (lamps), divided by the time in use, is the electrical power, which, As in mechanics, we measure in Watts (joules / second).

**Power is directly proportional to voltage and current.**

Mathematically, we have:

For example, in a 2200 W electric shower, connected to the 110V grid, we can calculate the current that flows through it: