you're right to question this 'derivation'... because its stupid!
E doesn't equal mc^2 for a photon, so imo you can't really equate the first two formulae you've quoted
you can find a theoretical tabulation of the 'mass-absorption coefficient' of every element between hydrogen and Uranium for X-ray energies in this link. My PhD project involves measuring some of these X-ray absorption coefficients, and the tabulation is pretty accurate...
I'm taking a QFT course and there is something that is bugging me. When we write out the equations in terms of generalised coordinates (q and p like in Lagrangian mechanics), it is always then taken as obvious that q and p satisfy the position momentum commutation relation. They arn't position...
I was just thinking how photons fit into QM, I've heard people speak of "photon wavefunctions".
In particular I am wondering whether its bound by the Uncertainty priciple, I guess it can't be... since we know its exact velocity (i.e delta(x) = 0, at least in a 1-d case =P) how could we...
I was just wondering about Heisenbergs matrix mechanics, what does it look like? is it still usefull to solve certain problems? does anyone know a decent link that explains it properly? (I've had a look but found nothing detailed enough)
I know Hilbert proved it was equivalent to...
Thanks for all the responses guys :)
And particular thanks go to pmb phy, for giving me EXACTLY what I wanted (a good first course in Lagrangian mechanics available on the web)
because it gives results that fit with experiment VERY well, e.g. using quantum theory you can predict the energy levels of most simple atoms/molecules. Its easy to test they are correct by looking at the wavelengths of light these atoms/molecules give off. I know of no other theory that can...
I've been trying to find a good introduction to the Lagrangian form of classical mechanics. Preferably something I can get over the web, since I'm not at Uni this year. I might like something particularly slow :-p
yes, it occurs in all the elements with nuclear spin in much the same way. I just chose Hydrogen (foolishly =P) because its the simplest element and it was easy to find confirmation of.
http://www.iiap.res.in/answers/galactic.html
The electron and proton in a hydrogen atom are like 2 bar magnets, normally there north and south poles are anti-alligned (like 2 bar magnets tend to sit). Very rarely the 2 particles make a "spin flip" and by doing this give off a photon of...
According to the bit of paper I was sent from the University, I have a degree in mathematical physics. It just meant I did 50/50 Maths/Physics subjects and didnt do any practical work