The power rating of a 400-Ω resistor is 0.25 W.What is the maximum voltage you can safely connect across its ends?
A)10 V
B)20 V
C)30 V
D)40 V
E)50 V

Question

Quizplus · Accepted Answer

The maximum voltage can be calculated using the power formula $P = \frac{V^2}{R}$, where $P$ is the power in watts, $V$ is the voltage in volts, and $R$ is the resistance in ohms. Rearranging the formula to solve for $V$, we get $V = \sqrt{P \times R}$. Substituting $P = 0.25$ W and $R = 400$ Ω, we get $V = \sqrt{0.25 \times 400} = \sqrt{100} = 10$ V.

The Power Rating of a 400-Ω Resistor Is 0