A conducting circular loop is placed in a uniform magnetic field B =50 mT with its plane perpendicular to the magnetic field. The radius of the loop…

A conducting circular loop is placed in a uniform magnetic field $\displaystyle \mathrm{B}=50 \mathrm{mT}$ with its plane perpendicular to the magnetic field. The radius of the loop is made to shrink at a constant rate of $\displaystyle 1 \mathrm{~mm} \mathrm{~s}^{-1}$. At the instant the radius of the loop is $\displaystyle 4$ cm , the induced emf in the loop is :