Classical Mechanics: Lecture 34 Notes

Overview

Only one lecture left.  Today is a 48 minute lecture on quantum mechanics, a segue into the next semester’s subject.  There are two cameramen in class, and most of the negros sit in the back.

Details

All physics of the 19th century and earlier are classical physics.  Almost all the mass of an atom is concentrated in a very small mass called the nucleus.  An atom is all vacuum.  Quantization is the discrete orbits that an atom can assume.

E = hf

h = 6.6 x 10^-34 J/s

c = wf

Allowed energy levels or orbits rise as the distance from the nucleus increases.  Some jumps might be UV, IR, blue, red and so on.

He gives the class a diffraction grating.  Sodium and mercury lights around town might look very interesting.

Is light a particle or a wave?  It is both.

wavelength = h/momentum = h/p

For macroscopic objects, the wavelength is ridiculously low.

HUP – Heisenburg Uncertainty Principle

dp dx >= h/(2pi)

The electron only has a velocity because it is confined!  Shocking result.

He goes through the typical grating experiments that most physics classes do.

Review

F = ma

P =mv

KE = k = .5mv2

PE = U = mgh