Question

A solenoid of inductance $L$ carrying a certain current is linked with a total magnetic flux $\varphi$. Now it is connected to a condenser with which it shares half of its initial energy. The total flux now linked with the solenoid is:

• A. $\frac{\varphi }{2}$
• B. $\frac{\varphi }{\sqrt{2}}$
• C. $\frac{\varphi }{2\sqrt{2}}$
• D. $\frac{\varphi }{4}$

Answer 1

The correct option is B $\frac{\varphi }{\sqrt{2}}$

Energy in indicator $=\frac{1}{2}L{i}^2$
With Energy transfer, $i$ becomes $i/\sqrt{2}$
Now since $\varphi =Li$
New $\varphi =Li/\sqrt{2}=\varphi /\sqrt{2}$
So, total flux will be $\varphi /\sqrt{2}$