A certain elastic conducting material is stretched into a circular loop. It is placed with its plane…

According to the Faraday's law of electromagnetic induction, the emf induced in a conducting loop is given by, $e=-\frac{d\varphi }{dt}$, here, $t$ is time and $\varphi =BA$ is magnetic flux.

Here, $e=\left|\frac{d\varphi }{dt}\right|=\frac{d\left(BA\right)}{dt}=B\frac{d\left(\pi r^2\right)}{dt}$

$$\begin{gathered} =B\pi \left(2r\frac{dr}{dt}\right) \\ =2\times \pi \times 0.1\times 0.8\times 2\times {10}^{-2} \end{gathered}$$

 $\approx 10 \mathrm{mV}$ (rounded off)