Question

Mathematical expression for electric power(P), where $I$ is current and $R$ is resistance, is;

• A. $P=IR$
• B. $P=\frac{I}{R}$
• C. $P=\frac{R}{I}$
• D. $P=I^{2}R$

Answer 1

The correct option is D

$P=I^{2}R$

Electric power is given by:
$P=VI$

From Ohm's Law, we know that $V=IR$
Therefore, electric power $=I\times IR=I^{2}R$