I'm trying to help with an Instructor's Guide for an introductory calc-based physics text, and it would really help if I could locate some lists of typical student difficulties with topics like ...

flux

induced E and B fields

Faraday's law

Lenz's law

DC circuits

AC circuits

Is there a better approach than just Googling "student difficulties with XXX," as I have been trying with rather inconsistent luck?

*Added--*

Thanks for the reminder! I actually found a copy of Randy Knight's book in the attic that I got from him at an AAPT meeting some years back. I can't believe I actually located it in my chaos ... great suggestion!