A circular copper ring of radius r translates in its plane with a constant velocity v. A uniform magnetic field b exists in the space in a direction perpendicular ot the plane of the ring. Consider different pairs of diametrically opposite points on the ring. (a) Between which pair of points is the emf? (b) Between which pair of points is the emf minimum? What is the value of this minimum emf?

Explanation

(a) The emf is highest between the diameter perpendicular to the velocity because here length perpendicular to velocity is highest.`
`E_(max)-vB 2R`
`(b) The length perpendicular to velocity is lowest as the diameter is parallel to the velocity `
`E=_(min)=0.`