*ping* physicists and engineers...

markdominus, who is a mathematician by training and a programmer by profession, has been attending undergraduate physics lectures and coming out more confused than he went in. It's a feeling I remember well from the last time I studied physics, and actually part of the reason I did my degree in mathematics - clearly I was never going to get to the bottom of this stuff if I were taught it by the physicists! :-) But then it turned out that physical applied maths was Really Really Hard, so I retreated back into pure maths.

Anyway, in one of his latest posts, he asks a series of questions about electromagnetism, and I realise to my shame that I don't know the answers to any of them. I did do a course with "electromagnetism" in the title once, but the other half of the title was "relativity", and wouldn't you know it, but relativity took up nearly all the teaching time. Anyway, I'd greatly like to know the answers to these: perhaps one of you physics or engineering types can help?

On the theory that I'll probably gain more understanding by thinking about it myself rather than just asking others, here are ( my guesses. )