Correct option: (B)
Explanation:
For equilibrium,
mg sin θ = f
Also, net torque should be zero.
The magnetic moment of the loop is perpendicualr to the plane.
∴ The torque due to magnetic force is τB = PB sin(180 – θ)
∴ τB = PB sin= PB sinθ = IπR 2B sin = IπR2B sinθ
This torque balances the torque due to friction about centre of mass.
∴ FR = IπR2B sinθ
or mg sin θ = πIRB sin θ