Question

The magnetic moment associated with a circular coil of $35$ turns and radius $25 \,cm$, if it carries a current of $11 \,A$ is

• A. $72.2 \, A\, m^{2}$
• B. $70.5 \, A\, m^{2}$
• C. $74.56\, A\, m^{2}$
• D. $75.56\, A\, m^{2}$

Answer 1

Answer: (D)

Given $N = 35$,
$r = 25\, cm$
$=25\times10^{-2}\,m$,
$I=11\,A $
Then magnetic moment associated with this circular coil
$M=NIA=NI\pi r^{2}=35\times11\times3.14\times\left(25\times10^{-2}\right)^{2}$
$=75.56\,A \,m^{2}$