A charged capacitor and an inductor are connected in series. At time t = 0 the current is zero, but the capacitor is charged. If T is the period of the resulting oscillations, the next time, after t = 0 that the charge on the capacitor is a maximum is:
A) T
B) T/4
C) T/2
D) T/1
E) 2T

Question

Quizplus · Accepted Answer

In a series LCR circuit, the charge on the capacitor and the current through the circuit oscillate sinusoidally with a period T. The maximum charge on the capacitor occurs when the current is zero and the voltage across the capacitor is a maximum. This happens at t = T/4, 3T/4, 5T/4, etc. 
However, at t = 0, the current is zero and the capacitor is charged, which means the voltage across it is also maximum. Therefore, the maximum charge on the capacitor will occur half a period later, i.e. at t = T/2. Thus, choice C is correct.

A Charged Capacitor and an Inductor Are Connected in Series