Electromagnetic Induction

A metallic rod of \(2 \mathrm{~m}\) length is rotated with a frequency \(100 \mathrm{~Hz}\) about an axis passing through the centre of the circular ring of radius \(2 \mathrm{~m}\). A constant magnetic field \(2 \mathrm{~T}\) is applied parallel to the axis and perpendicular to the length of the rod. The emf developed across the ends of the rod is :