Question

What is the S.I. unit of electrical power?

• A. watts
• B. joules
• C. volts
• D. ampere

Answer 1

The correct option is A watts

Electric power is the rate at which electric energy is transferred by an electric circuit. The SI unit of power is the watt, one joule per second.
It is the rate of doing work, measured in watts, and represented by the letter $P$. The electric power in watts produced by an electric current $I$ consisting of a charge of $Q$ coulombs every $t$ seconds passing through an electric potential (voltage) difference of $V$ is
$P=$ work done per unit time $=\frac{VQ}{t}=VI$
where,
$Q$ is electric charge in coulombs
$t$ is time in seconds
$I$ is electric current in amperes
$V$ is electric potential or voltage in volts.