An inductor of `2` henry and a resistance of `10` ohms are connected in series with a battery of `5` volts. The initial rate of change of current is

Options

A. `0.5amp//sec`
B. `2.0amp//sec`
C. `2.5amp//sec`
D. `0.25amp//sec`

Answer

C

Explanation

`i=(E)/(R)(1-e(-Rt//L)`
`(di)/(dt)=(E)/(R)e^(-(Rt)/(L)).(R)/(L)=(E)/(L)e^(-(Rt)/(L))`
`t=0, (di)/(dt)=(E)/(L)=(5)/(2)=2.5A//sec`