engineering "co-op" interview

<p>just got asked to interview for a co-op. what can i expect from a co-op? what's the difference between that, an internship, and a normal part time job?</p>

<p>also, how likely is it that they ask me technical questions about my field? im in the biomedical area, and there arent to many questions id feel competant answering, especially after all this time off in the summer. most of the things ive read said that for an internship type deal it should just be normal interview questions..</p>

<p>i obviously dont have time to cram semesters worth of material, but if he does ask technical questions that i cant answer, would it be ok to just say im a little rusty having not thought about it for a while but im sure i can pick up on it again.</p>

<p>also, it seems that it is professional to send a thank you note after the interview. is this necessary for a co-op/internship. i dont want to appear to be a kiss-ass if not. if so, does an email suffice?</p>