A thin flexible 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 :

Options

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

Answer

C

Explanation

`L=2piR`
`:.R=L//2pi`
`2T sin (d theta)=F_(m)`
For small angle `sin (d theta)=d theta`
`:. 2T(d theta)=I(dL)B sin 90^(@)=I(2R. D theta) . B`
`:.T=IRB=(ILB)/(2pi):.`