I have a book question I'm trying to understand:
The first bit is easy enough. The second part I was confused so I checked the solution:
B is into the page. The flux increases as the bar moves to the right, so the magnetic field of the induced current is out of the page inside the circuit. To produce magnetic field in this direction the induced current must be counterclockwise, so from b to a in the rod.
I thought I had a pretty good grip on increasing/decreasing magnetic field inducing negative/positive current(respectively). Maybe I'm missing something real trivial but I don't understand how flux increases as the bar moves. Why?