a conducting wire os mass `m` slides down two smooth conducting bars, set at an angle `theta` to the horizontal as shown in . The separatin between the bars is `l`. The system is located in the magnetic field `B`, perpendicular to the plane of the sliding wire and bars. The constant velocity of the wire is

Explanation

Along inclined plane the force acting downwards
`= mg sin theta` ….(1)
magnetic force acting upwards
`rArr F = Bil rArr B((Blv)/(R ))l`, `= (B^(2)l^(2)v)/(R )` ....(2)
From (1) and (2)
`(B^(2)l^(2)v)/(R ) = mg sin theta` , `v = (mgR sin theta)/(B^(2)l^(2))`