A metal rod of mass $$m$$ and length $$\ell$$ slides on frictionless parallel metal rails of negligible resistance. A resistance $$R$$ is connected between the rails at their ends as shown in the figure. A uniform magnetic field $$B$$ is directed into the plane of paper perpendicular to the plane of rails throughout the space. The rod is given an initial velocity $$v_0$$ towards right. No other force acts on the rod. Then