A wire of length $314\,cm$ carrying current of $14\,A$ is bent to form a circle. The magnetic moment of the coil is $........A- m ^{2}$. [Given $\left.\pi=3.14\right]$
A$10$
B$11$
C$54$
D$0$
JEE MAIN 2022, Medium
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B$11$
b $\frac{314}{100}=2 \pi R \quad R =0.5 m$
$\text { Magnetic Moment }= IA$
$=14 \times \pi R ^{2}$
$= 14 \times(3.14) \times \frac{1}{4}$3
$=10.99 \approx 11.00$
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