A uniform magnetic field of 0.4 T acts perpendicular to a circular copper disc 20 cm in radius. The disc is having a uniform angular velocity of 10 π…

A uniform magnetic field of $\displaystyle 0.4$ T acts perpendicular to a circular copper disc $\displaystyle 20$ cm in radius. The disc is having a uniform angular velocity of $\displaystyle 10 \pi \mathrm{rad} \mathrm{s}^{-1}$ about an axis through its centre and perpendicular to the disc. What is the potential difference developed between the axis of the disc and the rim ? $\displaystyle (\pi=3.14)$