Energy conservation in induced emf In the figure a square loop(of resistance R) is moving with a constant velocity v in a uniform magnetic field B directed perpendicular to the plane of the loop which  exist only to the left of the dotted line . A constant force F is being applied on the square loop in the right direction.

My teacher says that the power that we are delivering by F (P=F.v)
Gets converted into thermal energy dissipated by the loop(P=i^2xR).
I think that the power we are delivering is getting used to maintain a constant velocity of the loop against the negative work that is being done by the force of magnetic field on the loop(F b). If this is so, then where is the thermal energy that is being dissipated coming from?
Which argument is wrong?
And what exactly is happening in this problem in terms of energy and power?
 A: Here is an interesting question for you and your teacher to ponder:
If the loop was superconducting, would there still be a force? In that case, "where does the work go?"
Once you figure out the answer to that question, you will know where the energy goes in the first instance - and how it ends up with your teacher being right when you have a resistive loop.
UPDATE
When you pull on the loop, and it leaves the area of constant B, the loop experiences a change in flux. This results in an emf generated around the loop, and that in turn will cause a current to flow. The flow of the current reduces the change of the flux (because it tries to "restore" the flux lost). How well it succeeds depends on the resistance of the wire (since the emf is the thing that is given, you will get more current flowing if the resistance is lower. With sufficiently low resistance, you will basically cancel the change in field completely.)
What is the work you are doing? As you say, you are pulling against the force of the magnetic field, and what's really happening is that the work done extends the magnetic field (the loop "doesn't want to leave the magnetic field, so it makes more"). But as it does so by making additional current, that current in the loop experiences resistance, and this becomes heat. And then the loop no longer sees the same magnetic field.
If only it was a superconducting loop - it would be able to hold on to the magnetic field "forever".
