A hypothetical magnetic field existing in a region is given by `vecB= B_0 vece_r,` where `vec r` denotes the unit vector along the radial direction. A circular loop of radius a, carrying a current I, is placed with its plane parallel to the x-y plane and the centre at (0,0, d) .Find the magnitude of the magnetic force acting on the loop.

Explanation

Required magnatic force
` F = int dF = int( _(0) ^(2 pi a ) idl b sin sin thieta `
` = iB , (a)/(sqrt a^ (2) + d^(2) ) int _(0) ^(2 pi a) dL `
` = (2 pi a^(2) B /(sqrt a^(2) + d^(2) ).