question_answer

What fraction of the energy drawn from the charging battery is stored in a capacitor?

A)  75%                                      

B)  100%

C)  25%                                      

D)  50%

Correct Answer: C

Solution :

\[{{p}_{i}}m\,u\] \[=\,m\,20\] \[\therefore \]  \[|{{p}_{i}}|\,=\,|{{p}_{2}}+{{p}_{3}}|\] \[{{p}_{3}}=\sqrt{p_{i}^{2}+{{({{p}_{2}})}^{2}}}\] \[\frac{m\upsilon }{2}=\sqrt{{{m}^{2}}{{(20)}^{2}}+{{\left( \frac{m}{2}30 \right)}^{2}}}\] \[\frac{m\upsilon }{2}=\frac{m}{2}\sqrt{{{(40)}^{2}}+{{(30)}^{2}}}\] \[\upsilon =50\,m/\sec \]