Q.17. A vertical copper disc of diameter 40 cm makes 30 revolutions per second about a horizontal axis passing through its centre. A uniform field ${10}^{-2} wb/m^2$ acts perpendicular to the plane of the disc. Potential difference developed between centre of disc and rim of disc is
(a) $5.472\times$ ${10}^{-2}V$
(b) 1.432$\times {10}^{-2}V$
(c) 3.768$\times {10}^{-2}V$
(d) 6.693$\times {10}^{-2}V$