In the circuit shown, the cell is deal. The coil has an inductance of `4H` and zero resistance. `F` is a fuse of zero resistance and will blow when the current through it reaches `5 A`. The switch is closed at `t=0`. The fuse will blow:

Options

A. almost at once
B. after `2` sec
C. after `5` sec
D. after `10` sec

Answer

D

Explanation

`E=L(dl)/(dt)`
or `(dl)=(E)/(L)(dt)`
or `I=(2)/(4)t=0.5t`
For `I=5A,t=10`sec