By what factor does the maximum energy stored in a series RL circuit change if the resistance is doubled and the inductance is tripled in the circuit?
A)0.67
B)0.75
C)0.50
D)1.5

Question

Quizplus · Accepted Answer

The maximum energy stored in an inductor in a series RL circuit is given by the formula $E = \frac{1}{2}LI^2$, where $L$ is the inductance and $I$ is the current. When the resistance is doubled, the current in the circuit is halved (since $I = V/R$, and $V$ is constant for a given power source), and when the inductance is tripled, the energy stored becomes $E' = \frac{1}{2}(3L)(\frac{I}{2})^2 = \frac{3}{4}\frac{1}{2}LI^2$. Therefore, the energy stored changes by a factor of 0.75.

By What Factor Does the Maximum Energy Stored in a Series