Two identical conducting rings A & B of radius R are in pure rolling over a horizontal conducting plane with same speed (of centre of mass) `upsilon` but in opposite direction. A constant magnetic field B is present pointing inside the plane of paper. Then the potential difference between the highest points of the two rings, is :

Options

A. zero
B. `2 Bvr`
C. `4 Bvr`
D. None of these

Answer

C

Explanation

Alternate-Considering rotation of diameter about lowest point: `e=(Bomega(2r)^(2))/2=2Bvr` at `A` with respect to plane (since pure rotation ). and `e=-2Bvr`at `B` with respect to plane So, potential difference between these two points=`4Bvr`
Hence `(c )`