If in a coil rate of change of area is `5m^(2)//millisecond` and current become `1 amp` from `2 amp` in `2xx10^(-3)` sec. magnitude of field id `1 teslsa` then self-inductance of the coil is

Options

A. `2H`
B. `5H`
C. `20H`
D. `10H`

Answer

D

Explanation

`Nvarphi=Liimplies(Ndvarphi)/(dt)=(Ldi)/(dt)impliesNB(dA)/(dt)=(Ldi)/(dt)`
`implies(1xx1xx5)/(10^(-3))=Lxx((2-1)/(2xx10^(-3)))impliesL=10H`