Question

$10$ ampere current flows through a coil of radius $\frac{1}{\sqrt{\pi }}m$ and having $20$ turns. The magnetic moment of the coil will be:

• A. $200ampere-m^2$
• B. $200ampere-m$
• C. $200coulomb-m$
• D. $200coulomb-m^2$

Answer 1

The correct option is A $200ampere-m^2$

Magnetic moment $\mu$ is given

as $\mu =nIA$

where $n:$ no. of turns

$I:$ Current

$A:$ Area

Given $J=10amp$

$n=20$

$r=\frac{1}{v\pi }m$

Area of circle $\pi r^2$

$=\perp$

so

$\mu =1\times 20\times 10Amp-m^2$

$\mu =200Amp-m^2$