Question

A vertical conducting ring of radius $R$ falls vertically in a horizontal magnetic field of magnitude $B$. The direction of $B$ is perpendicular to the plane of the ring. When the speed of the ring is $v$,

• A. no current flows in the ring
• B. $A$ and $D$ are at the same potential
• C. $C$ and $E$ are at the same potential
• D. the potential difference between $A$ and $D$ is $2BRv$, with $D$ at a higher potential
• E. answer required

Answer 1

Answer: (A), (C)

The correct options are
A no current flows in the ring
C $C$ and $E$ are at the same potential

When a conducting element travels perpendicular to a magnetic field, emf is induced in direction perpendicular to both velocity and field. Thus potential at D is greater than that at C and E, which are greater than that at A.

Hence, potential at D is higher than that at A.

Since, C and E are both along same line of velocity vector, there is no potential difference between them.