Question

The area of a coil is 'A'. The coil is placed in a magnetic field which changes from 'B₀' to 4B₀' in time 't'. The magnitude of induced e.m.f. in the coil will be ____________.

Options

• `(4 "AB"_0)/"t"`

• `(4 "B"_0)/"At"`

• `(3 "B"_0)/"At"`

• `(3 "AB"_0)/"t"`

Answer 1

The area of a coil is 'A'. The coil is placed in a magnetic field which changes from 'B₀' to 4B₀' in time 't'. The magnitude of induced e.m.f. in the coil will be `(3 "AB"_0)/"t"`.

Explanation:

`"dB"/"dt" = "d"/"dt" (4 "B"_0 - "B"_0)`

`= (3"B"_0)/"t"`

`"e" = ("d"phi)/"dt" = "d"/"dt"  "A". 3"B"_0`

`= (3"B"_0"A")/"t"`