Classical Electrodynamics was nothing short of a nightmare for me when I was still studying. It came to a point where I had to solve 3 problems from a book so frighteningly called Classical Electrodynamics just to complete the subject.
Solved the first two after a while, was confident with my answers, until i came across a wall. The king of the hill. The level boss. Problem 11.28.
I did everything that I could and eventually realized that the dragon was hovering above me, and there was nothing I could do to fly up there on my own. I had to borrow someone else’s wings. Certainly not one from my teacher, who was, although powerful, a mere mortal who cared less about his students than he did the chalk dust on the tip of his nose.
If I had to go up there and slay the dragon, I have to do so with the wings of an immortal who gave birth to this dragon with the sole purpose of unleashing hell as a manner of segregating the strong from the unprepared. I have to borrow the wings of Mr. John David Jackson.
Okay that was too dramatic. I just actually emailed the author and asked for help, but not expecting any reply nonetheless, at least a real one at that, since I was half-expecting that at best, a bot would reply with some sort of programmed message.
Okay so here was my message:
hello Mr. Jackson,
I need to solve problem 11.28 of your book Classical Electrodynamics Third Edition by the end of this week to complete my grade. Please help me! thanks
In letter a.) how do I transform r prime to R?
In letter b.) I don’t know how to start.
In letter c.) I solved this one already.
Thank you very much! Mabuhay!
Neal Alfie Lasta
Iligan City, Philippines
You can sense that it was a half-hearted email, and that fact alone all the more contributed to my amazement and amusement when he came back with this message:
Dear Neal Lasta,
It has been quite a few years sincei received a request for help with a
problem in homework, and with a deadline. Do you know the word, chutzpah
I will give you a hint or two, provided you tell your instructor that
you got help from me by attaching this e-mail to your solution. Agreed?
Part (a): Time and space oordinates transform in a certain way under
Lorentz transformations and so do the scalar and vector potentials. Use
those expressions and then specialize to first order in velocity.
Part (b): The Lorenz condition is stated in Chapter 6. Just calculate
the left-hand side and see whether you get zero.
J. D. Jackson
Words from the maestro! And his hints really helped. To some extent at least. I still had a lot of work after borrowing his wings and eventually landing at the back of the dragon. Apparently, my sword was too blunt for dragon skin, as feather is to stone. But I was there, and I would chew at his back, slowly and surely, tickling it more than I was hurting it at first, but eventually wounding it open.
Sorry I had to bring back that melodramatic analogy again.