Question

A circular coil of radius 10 cm and 100 turns carries a current $1A$. What is the magnetic moment of the coil?

• A. $3.142\times {10}^{4}A{m}^2$
• B. ${10}^{4}A{m}^2$
• C. $3.142A{m}^2$
• D. $3A{m}^2$

Answer 1

The correct option is C $3.142A{m}^2$

Given : $r=10$ cm $=0.1$ m $N=100$ tuns $I=1A$

Area of the circular coil $A=\pi r^2=3.142(0.1{)}^2$ $m^2$

Magnetic moment $\mu =NIA$

$\therefore$ $\mu =\left(100\right)\left(1\right)\left(3.142\right)(0.1{)}^2=3.142$ $A{m}^2$