Magnetic field is uniform and has a magnitude B in the interior of a very solenoid far from its ends. One of the ends of the solenoid is closed with a thin flat plastic cover. A single small electrical loop of radius R lies on the cover so that its center is on the axis of the solenoid. The electrical current flowing in the loop in I. If the mechanical tension in the loop's wire is `(BIR)/(x)`, then the value of x :

Explanation

B at end =`1/2` B at interior =`1/2` B
`IdL(B/2)=2T sind theta`
`dL=R(2d theta)`
`I R.2d thetaB/2=2T d theta`
`T=(BIR)/2`