If a lamp has resistance of 120 W when it operates at 100 W,what is the applied voltage?
A)110 V
B)120 V
C)125 V
D)220 V

Question

Quizplus · Accepted Answer

The correct answer is A because the power of a lamp is given by the formula P = V^2 / R, where P is the power in watts, V is the voltage in volts, and R is the resistance in ohms. If the lamp has a resistance of 120 ohms and operates at 100 watts, then the applied voltage is V = sqrt(P * R) = sqrt(100 * 120) = 110 volts.

If a Lamp Has Resistance of 120 W When It