A tree is just a graph of a stack over time. Completely unrelatedly, here‘s Joel on Software on ‘People who are Smart but don’t Get Things Done’: These kind of people can be identified because they love to point out the theoretical similarity between two widely divergent concepts. For example, they will say, “Spreadsheets are [...]
Or: “How photons and electrons say hello” Low energy — Photoelectric effect This is the first one you learn: a photon knocks an electron out of its atomic orbit. It is most likely to occur at low energies… as you move up in energy it becomes more likely that the photon will be scattered rather [...]
Some people have numbers as their Twitter names. Which ones? The full-size image is 1000 pixels high by 1000 pixels wide. Each pixel represents a number from 0 to 999,999. The row number gives the first three digits (0-999), the column number gives the last three digits (0-999)… so the pixels are ordered like letters [...]
So the electron in the hydrogen atom is just a particle in a spherically-symmetric 1/r potential… you’ve got a ladder of energy eigenvalues indexed by a quantum number n. The nth eigenvalue has degeneracy n2, but that’s cool; picking an axis z, the total angular momentum operator L and the z-axis angular momentum operator Lz [...]
import re q=’"’ s=’\\’ nl=’\n’ x="import re\"+nl+\"q=’\"+q+\"’\"+nl+\"s=’\"+s+s+\"’\"+nl+\"nl=’\"+s+\"n’\"+nl+\"x=\"+q+re.sub(‘\"’,s+’\"’,x)+q+nl+\"print \"+q+x" print "import re"+nl+"q=’"+q+"’"+nl+"s=’"+s+s+"’"+nl+"nl=’"+s+"n’"+nl+"x="+q+re.sub(‘"’,s+’"’,x)+q+nl+"print "+q+x Hey, I didn’t say it was pretty. Note how the syntax highlighter completely throws in the towel by line 3. :(
Having taken GRE Physics practice test 8677, it is clear that there are some very specific holes in my knowledge… Three main things: atomic physics (hydrogen atom: spectra? K series? Zeeman effect? Stark effect? selection rules? chemistry/orbitals?) nuclear physics (decay, what with \(\beta\)s and \(\alpha\)s and antineutrinos; binding energies) optics (diffraction, Rayleigh condition, indices of [...]