A coil in the shape of an equilateral triangle of side l is suspended between the pole pieces of a permanent magnet such that`vec B ` is in the plane of the coil. If due to a current i in the triangle a torque `tau` acts on it, the side l of the triangle is

Options

A. `(2)/(sqrt(3))((tau)/(B.i))^(1/2)`
B. `2((tau)/(sqrt(3)B.i))^(1/2)`
C. `(2)/(sqrt(3))((tau)/(B.i))`
D. `(1)/(sqrt(3)) (tau)/(B.i)`