A conducting circular loop is placed in a uniform magnetic field of...

The data given is

$B = 0 . 4TR = 2 \times {10}^{- 2}m$

It is given that $\dfrac{dR}{dt} = {10}^{- 3}m{s}^{- 1}$

Area of the loop is $A = \pi{R}^{2}$

So, $\dfrac{dA}{dt} = 2\piR\dfrac{dR}{dt}$

The flux is,

$ϕ = 2\piR\dfrac{dR}{dt} \times B$

So, the magnitude of emf is

$ε = 2 \times \dfrac{22}{7} \times 2 \times {10}^{- 2} \times {10}^{- 3} \times 0 . 4$

$= 5 . 028 \times {10}^{- 5}V = 50 . 28\mu V \approx 50\mu V$