The magnetic flux `(phi)` linked with the coil depends on time `t` as `phi=at^(n)`, where `a` and `n` are constants. The emf induced in the coil is `e`

Options

A. If `0 lt n lt 1, e ne 0` and |e| decrease with time
B. If `n = 1`, e is constant
C. If `n gt1, |e|` increase with time
D. None of these

Answer

4

Explanation

`phi = "at"^(n)`
`e = (dphi)/(dt) = "nat"^(4-1)`
If `0 lt n lt 1` power of t is - ve hence `tdarreuarr`
If n=1 , `phi`= at , `e=(dphi)/(dt) = a`
If `n gt 1`
So from the expression
`e = nat^(n-1)`
`edarr as t uarrs`