Two rings of radii 5m and 10m move in opposite directions with velocity 20 m/s and 10 m/s respectively, on a conducting curface S. There is a uniform magnetic field of magnitude `0.1T` perpendicular to the plane of the rings. Find the potential difference between the highest points of the two rings.

Explanation

The above situation can be drawn as

As we know, induced emf in a rod is given by e = Bvl.
So, for rod PQ, e = Bvl = `0.1xx10xx10=10V`
For rod RS, e = Bvl = `0.1xx20xx5=10V`
So, the net emf produced in above figure is given by
`V_(P)-10V-10V=V_(S)rArrV_(P)-V_(S)=20V`