An RLC circuit has a sinusoidal source of emf. The average rate at which the source supplies energy is 5 nW. This must also be:
A) the average rate at which energy is stored in the capacitor
B) the average rate which energy is stored in the inductor
C) the average rate at which energy is dissipated in the resistor
D) twice the average rate at which energy is stored in the capacitor
E) three times the average rate at which energy is stored in the inductor

Question

Quizplus · Accepted Answer

The average rate at which energy is supplied by the source must be equal to the average rate at which energy is dissipated in the circuit, since energy cannot be created or destroyed. Therefore, the answer is C. The average rate at which energy is stored in the capacitor or inductor may fluctuate over a cycle, but the total energy stored over a cycle must be zero (since the energy stored in one half of the cycle is returned to the source in the other half). Therefore, choices A, B, D, and E are not correct.

An RLC Circuit Has a Sinusoidal Source of Emf