Magnitude of the induced current in the loop

[chinex9a]

Homework Statement

A rectangular conducting loop of dimensions l×w and resistance R rests in the plane of a long
straight wire as shown. The closest edge of the loop is a distance a from the wire. The current in
the wire is in the upward direction and increases at a constant rate from I to 3I in time Δt.
Find the magnitude of the induced current in the loop.

Homework Equations

Maybe magnetc flux equation ABcos(theta) and magnetic field of a wire = (u*I)/(2*pi*d)

The Attempt at a Solution

Used magnetic field equation (not sure what to use for d) and don't know what to do from there.

 

[vela]

The magnetic field varies with the distance from the wire, so the magnetic field through the loop isn't a constant. That means you can't simply take some value for B and multiply it by the total area of the loop to find the total flux. You're going to have to integrate.

 

[chinex9a]

But we are trying to find the induced current. How do we come about that?

 

[vela]

That's a good question. What do you think?