Problem 3.289

A rectangular loop with a sliding connector of length $l$ is located in a uniform magnetic field perpendicular to the loop plane (Fig. 3.79). The magnetic induction is equal to $B$. The connector has an electric resistance $R,$ the sides $A B$ and $C D$ have resistances $R_{1}$ and $R_{2}$ respectively. Neglecting the self-inductance of the laop, find the current flowing in the connector during its motion with a constant velocity $v$.