A metallic rod of length L

A metallic rod of length L is rotated with
angular frequency of with one end hinged at the centre and the other end at the circumference of a circular metallic ring of radius l, about an axis passing through the centre and perpendicular to the plane of the ring. A constant and uniform magnetic field B, parallel to the axis is present everywhere. Deduce the expression for the emf between the centre and the metallic ring.

Angular velocity of rod