A metallic rod of mass per unit length is lying horizontally on a smooth inclined plane which makes an angle of with the horizontal. The rod is not allowed to slide down by flowing a current through it when a magnetic field of induction is acting on it in the vertical direction. The current flowing in the rod to keep it stationary is [2018]
(4)

Mass per unit length of a metallic rod is
Let be the current flowing.
For equilibrium,