Question

A conducting circular loop of area 1 $m{m}^2$ is placed coplanarly with a long, straight wire at a distance of 20 cm from it. The straight wire carries an electric current which changes from 10 A to zero in 0.1 s. Find the average emf induced in the loop in 0.1 s.

Answer 1

Here $A=1m{m}^2,$

i =10 A

d=20 cm, dt =0.1 s

$e=\frac{d\varphi }{dt}$

$=\frac{B.A}{dt}=\frac{{\mu }_{0}i}{2\pi d}\times \frac{A}{dt}$

$=\frac{4\pi \times {10}^{-7}\times 10}{2\pi \times 2\times {10}^{-1}}\times \frac{{10}^{-8}}{1\times {10}^{-1}}$

$=1\times {10}^{-8}V$