Question

A current of $1A$ is flowing in a coil of $10$ turns having radius $10cms$. Its magnetic moment will be

• A. $3140A{m}^2$
• B. $100A{m}^2$
• C. ${\mu }_{0}A{m}^2$
• D. $0.314A{m}^2$

Answer 1

Answer: (D)

$0.314A{m}^2$

$A=\pi r^2=3.14\times {(10\times {10}^{-2})}^2=3.14\times {10}^{-2}$
$N=10$
$i=1A$
$\therefore \mu =NiA=10\times 1\times 3.14\times {10}^{-2}=0.314A{m}^2$