A conducting circular loop is placed in a uniform magnetic field $0.04 \mathrm{~T}$ with its plane perpendicular to the magnetic field. The radius of the loop starts shrinking at $2 \mathrm{~mm} / \mathrm{s}$. The induced emf in the loop when the redius is $2 \mathrm{~cm}$ is :

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Aicharya · Accepted Answer

$\begin{aligned} \mathrm{e} & =\frac{\mathrm{d} \phi}{\mathrm{dt}}=\frac{\mathrm{d}}{\mathrm{dt}}\left(\mathrm{B} \pi \mathrm{r}^2ight) \ & =2 \pi \mathrm{rB} \frac{\mathrm{dr}}{\mathrm{dt}} \ & =2 	imes \pi 	imes 2 	imes 10^{-2} 	imes 4 	imes 10^{-2} 	imes 2 	imes 10^{-3} \ & =3.2 	imes 10^{-6} \pi \mathrm{Vol}=3.2 \pi \mu \mathrm{V} \end{aligned}$

A conducting circular loop is placed in a uniform magnetic field $0.04 \mathrm{~T}$ with its plane…

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