Question

Magnetic field induction at the center of a circular coil of radius 5cm and carrying a current $0.9A$ is :
( in S.I. units)

• A. $\frac{1}{{ϵ}_0\times {10}^{16}}$
• B. $\frac{{10}^{16}}{{ϵ}_0}$
• C. $\frac{{ϵ}_0}{{10}^{16}}$
• D. ${10}^{16}{ϵ}_0$

Answer 1

The correct option is A $\frac{1}{{ϵ}_0\times {10}^{16}}$

$B=\frac{{\mu }_{o}i}{2r}$
${\mu }_0{ϵ}_0=\frac{1}{c^2}$
${\mu }_0=\frac{1}{{ϵ}_0\times 9\times {10}^{16}}$
$\therefore B=\frac{1\times 0.9A}{{2ϵ}_0\times 9\times {10}^{16}\times 5\times {10}^{-2}}$
$B=\frac{1}{{ϵ}_0\times {10}^{16}}$