Question for electromagnetic induction

[shubhxxx]

a conducting rod of length 1 m is rotated with an angular frequency of 400/s about an axis normal to the rod passing through one of its ends .the other end of the rod is in contact with a circular metallic ring. a constant magnetc field of 0.5T parallel to the axis exists in the region.find the emf induced between the ends of the rod.

 

[cragar]

I think you might be able to take the time derivative of magnetic flux which is voltage.
So it will be , Flux= A(B)cos(wt)
where A is the Area B is the field strength
and w is the angular frequency.