A metallic ring of mass m and radius l (ring being horizontal) is falling under gravity in a region having a magnetic field. If z is the vertical directoin, the z-component of magnitude field is `B_z = B_0(1+lambda+lambdaz)`. If R is the resistance of the ring and if the ring falls with a velocity v, find the energy lost in the resistacne. If the ring has reached a constant velocity, use the conversation of energy to determine v in terms of m, B, `lambda` and acceleration due to gravity g.