Faraday’s law

A circular conducting disc of radius $0.25\,\text{m}$ rotates at $40\,\text{revolutions s}^{-1}$ in a uniform magnetic field of flux density $0.20\,\text{T}$ perpendicular to the disc. Using Faraday’s law, calculate the magnitude of the e.m.f. induced between the centre and the rim of the disc.