A magnetic field of `2xx10^-2T` acts at right angles to a coil of area `100 cm^2` with 50 turns. The average e.m.f. induced in the coil is 0.1 V, When it is removed form the field in the time t. The value of t is

Explanation

`B=2 xx 10^(-2)"wbm"^(-2)`
Number of turns in the coil = N= 50
A=1000 `"cm"^(2)=1000 xx 10^(-4)"m"^(2)`
A= 0.1 `"m"^(2)`
`dt=(1)/(10)s=0.1s `
Let `phi_(1)=` Magnetic flux linked with the coil
when coil lies inside the magnetic field .
`phi_(1)=NBA cos theta`
When magnetic field is at right angle to the
coil then angle between `overset rarr Band overset rarr A` is `0^(@)`
`:. phi_(1)=50xx 2 xx10^(-2)xx0.1xx cos 0`
= 0.1 wb
When the coil is removed from the magnetic
field then B=0
and hence magnetic flux linked with coil = `phi_(2)=0`
`"Induced emf"=e=((phi_(2)-phi_(1)))/(dt)`
`e=((0-0.1))/(0.1)=1"volt"`