Question

If maximum energy is stored in capacitor at $t = 0$ then find the time after which current in the circuit will be maximum.

• A. $\frac{\pi}{2}$ ms
• B. $\frac{\pi}{4}$ ms
• C. $\pi$ ms
• D. 2 ms

Answer 1

Answer: (B)

In L-C oscillation total time in one complete cycle.
$T=2\pi\sqrt{LC}$
$T=2\pi\sqrt{25\times10^{-3}\times10\times10^{-6}}$
$T=2\pi\sqrt{25\times10^{-8}}$
$T=2\pi\times5\times10^{-4}$
$T=\pi\times10^{-3}$ sec
after time $\frac{T}{4}$ capacitor is fully closed
then $\frac{T}{4}=\frac{\pi\times10^{-3}}{4}=\frac{\pi}{4}$ ms