What is the unit used to measure electrical power?

What is the unit used to measure electrical power?

• A. Watt
• B. Joule
• C. Volt
• D. Ampere

Answer: (A)

Power is the rate at which energy is transferred or used in a circuit, so the unit must express energy per unit time. In electricity, power equals current times potential difference (P = V × I). The units volt and ampere multiply to give volt-ampere, which is defined as a watt. Since a watt is one joule per second, the watt is the unit for electrical power. The joule is an energy unit, not a rate; the volt measures potential difference, and the ampere measures current.

Power is the rate at which energy is transferred or used in a circuit, so the unit must express energy per unit time. In electricity, power equals current times potential difference (P = V × I). The units volt and ampere multiply to give volt-ampere, which is defined as a watt. Since a watt is one joule per second, the watt is the unit for electrical power. The joule is an energy unit, not a rate; the volt measures potential difference, and the ampere measures current.