Introduction, discussion of syllabus
What is quantum mechanics (vs. what is classical mechanics?)
Breakdown of classical physics, Blackbody radiation.
Next lecture: Planck's resolution of blackbody radiation, more breakdowns of classical physics: Photoelectric, Compton scattering...
SPECIAL NOTE ON UNITS
When possible, we will use cgs units (cm, grams, seconds are the basic units) but sometimes other units like angstroms and eV's.
Here's a summary of the most important units and constants we'll use:
1 eV = 1 electron volt = K.E. acquired by electron accelerated through a potential of 1 Volt:
1 ev = 1.602 * 10^-12 erg (unit of energy)
1 A = 1 Angstrom = 10^-8 cm (unit of length)
1 F = 1 Fermi = 1 femtometer = 10^-13 cm (unit of length)
1 amu = 1 atomic mass unit = 931.5 MeV = 1.49 * 10^-3 erg
m_e = electron mass = 0.511 MeV = 8.19*10^-7 erg
(Note: the last two are energies on the rhs, but the lhs is a mass!! We are sneakily assuming the formula E=mc^2, so I multiplied t he electron mass by c^2 to get the right side) Of course,
c = speed of light = 3*10^10 cm/s
More on units:
= "h-bar" = Planck's constant/(2 Pi) = h /(2 Pi)
= 6.626*10^-27 erg sec/(2 Pi) = 1.054*10^-27 erg sec
c (= hbar c)
has units of [erg cm] = [energy length],
c = hbar c
= 200 MeV fm = 2000 ev Angstroms. (Handy to remember!)
Charge of an electron, e = 4.803 *10^-10 esu (cgs)
I'll try to stick to cgs units when dealing with E+M, so there are no
's,
and for example
(units on that last equation are
[dynes] = [esu * statvolts/cm] + [esu * (cm/sec) * gauss / (cm/sec)]
Note that e^2/r is an energy (potential energy of two electrons, r apart!)
so [e^2] = [energy * length] = [
c]
* (some number)
In cgs units, e^2/(
c)
= 1/137 =
,
the fine structure constant
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Email: Steven.Pollock@colorado.edu