1. The problem statement A current I passes through a straight conducting wire located within this page. Rectangular circuit ABCD on the page is moving away from the straight conducting wire with speed v, while side AB remains parallel with the current I. The length of side AB is 2a, and the length of side AD is 2b. The resistance of the circuit is R. How much current flows through circuit ABCD when the center O of the circuit is distance r from the straight wire? The magnetic permeability of a vacuum is m, and the magnetic flux density created by the circuit's current is negligible. Please help me!