A metal bar AB can slide on two parallel thick metallic rails separated by a distance l. A resistance R and an inductance L are connected to the rails as shown in the figure. A long straight wire carrying a constant current `I_(0)` is placed in the plane of the rails and perpendicular to them as shown. The bar AB is held at rest at a distance `x_(0)` from the long wire. At t=0, it is made to slide on the rails away from wire. Answer the following questions.
Find a relation among i, `(di)/(dt) and (d phi)/(dt)`, where i is the current in the circuit and phi is the flux of the megnetic field due to the long wire through the circuit.