Electric power

Definition

Electric power is the rate at which electrical energy is transferred by an electric circuit. It is typically measured in watts (W).

5 Must Know Facts For Your Next Test

1. Electric power can be calculated using the formula $P = IV$, where $P$ is power, $I$ is current, and $V$ is voltage.
2. Another formula for electric power when resistance ($R$) is known is $P = I^2R$ or $P = \frac{V^2}{R}$.
3. The unit of electric power, the watt, is equivalent to one joule per second.
4. Electric power in household appliances is usually rated in kilowatts (kW).
5. Power ratings of devices help determine how much energy they consume over time.

Review Questions

• What formula would you use to calculate electric power if you know the current and voltage?
• How does the unit watt relate to joules and seconds?
• If a device has a high resistance, how does that affect its electric power consumption assuming constant voltage?

Related terms

Voltage:

The potential difference between two points in an electric field that causes current to flow.

Current:

The flow of electric charge through a conductor, measured in amperes (A).

Resistance:

A measure of the opposition to current flow in an electrical circuit, measured in ohms (Ω).