A long straight wire is oriented in the z direction and carries a current I. A square loop with sides of length w is in the xz-plane with its nearest edge a distance d from the wire. In time of t, the square loop moves a distance of l closer to the wire. What is the emf induced in the loop while its moving?

Answer 1

Write B as a function of distance from the wire, and integrate B over the loop to get BA as a function of the changing B per time.