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.
$T=2\pi \sqrt{LC}$
$T=2\pi \sqrt{25\times 10^{-3}\times 10\times 10^{-6}}$
$T=2\pi \sqrt{25\times 10^{-8}}$
$T=2\pi \times 5\times 10^{-4}$
$T=\pi \times 10^{-3}$ sec
after time $\frac{T}{4}$ capacitor is fully closed
then $\frac{T}{4}=\frac{\pi \times 10^{-3}}{4}=\frac{\pi }{4}$ ms