Question

A thin wire of length `L` is connected to two adjacent fixed points and carries a current `I` in the clockwise direction , as shown in the figure. When the system is put in a uniform magnetic field of strength `B` going into the plane of the paper , the wire takes the shape of a circle . The tension in the wire is

A. `IBL`
B. `(IBL)/(pi)`
C. `(IBL)/(2pi)`
D. `(IBL)/(4pi)`

Answer 1

Correct Answer - C
`L = 2pi r rArr r = (L)/(2pi)`
`T = Bir = (BIL)/(2pi)`