As shown in the figure below, 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 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 of the circuit (O) is distance r from the straight wire?
B = μ0 I / (2πd)
V = I.R
Faraday's and Len's Law
The Attempt at a Solution
emf will be produced because there is change in magnetic field experienced by the rectangular wire as it is moving away from the straight wire but I don't know how to find the rate of change of magnetic field.
I have tried to find the magnetic field at AB and CD:
B at AB = μ0 I / (2π (r - b))
B at CD = μ0 I / (2π(r+b))
Difference of magnetic field between AB and CD = μ0 I 2b/ (2π(r2-b2))
I don't even know why I found those things above, I just tried anything. And also, what is v? is it 2b/t? or is it b/t?