If the resistance in a constant voltage circuit is doubled, the power dissipated by that circuit will
A) increase by a factor of four.
B) increase by a factor of two.
C) decrease to one-fourth its original value.
D) decrease to one-half its original value.

Question

Quizplus · Accepted Answer

Power dissipated in a circuit is given by P = V^2/R, where P is power, V is voltage, and R is resistance. If the resistance is doubled, the new power becomes P_new = V^2/(2R), which is half of the original power, hence the power decreases to one-half its original value.

If the Resistance in a Constant Voltage Circuit Is Doubled