Question

Determine the time when the energy stored in the capacitor first exceeds that in the inductor.

• A. $61.2\mu s$
• B. $63.2\mu s$
• C. $68.2\mu s$
• D. $73.2\mu s$

Answer 1

The correct option is B $63.2\mu s$

$\frac{q^2}{2C}>\frac{1}{2}L{i}^2$
or $\frac{{\left(10t^2\right)}^2}{2\times {10}^{-6}}>\frac{1}{2}\times {10}^{-3}\times {\left(20t\right)}^2$

or $t^2>40\times {10}^{-10}$
or $t>63.2\times {10}^{-6}s$
or $t>63.2\mu s$