Two conducting rings of radii `r` and `2r` move in apposite directions with velocities `2 upsilon` and `upsilon` respectively on a conducting surface `S`. There is a uniform magnetic field of magnitude `B` perpendicular to the plane of the rings. The potential difference between the highest points of the two rings is
![image](https://learnqa.s3.ap-south-1.amazonaws.com/images/1612250969138080201612250969.png)