Modern Physics

the week of March 22  -  26

this week's readings

    Monday, Mar 22            finish reading section 2.5 on the Compton effect

    Tuesday, Mar 23            no new reading, but there are still 4 questions left
                                            unanswered from last thursday and yesterday:
                                            a) why does the Compton effect use x-rays
                                                (and not, say, visible light?)
                                            b) how did people know the first crystal plane separations?
                                            c) why (when measuring the wavelength of light with a
                                                diffraction grating) must the separation of the gratings
                                                be comparable to the wavelength of light?
                                            d) why is the Compton effect evidence for particle-like behavior of light?

    Thursday, Mar 25            work on photoelectric effect, see below

    Friday, Mar 26                read the Feyman article, "The Quantum Behavior of Electrons"
                                            as you read, make a table of the various experiments' details, the results
                                                of each, etc.
                                            try to reproduce the mathematics; you know enough to do it; hint: complex
                                                algebra required


this week's assignments

    Monday, Mar 22             bring to class:  a print-out of your best function fit
                                                    to the current-vs-voltage plots from the photoelectric
                                                    effect data...
                                        you should bring at least one for each color (and you should
                                                    have tried more functions than the one (best) that you
                                                    bring; you must use the same function for all light colors

    Tuesday, Mar 23            laser lab due

    Thursday, Mar 25 to be done by class:
                                            1) calculate means and standard deviations for the each of the 3 colors'
                                                directly-measured stopping voltages
                                            2) finalize your function fit, and perform the extrapolation to each of your
                                                current-vs-voltage data sets to obtain an extrapolated stopping voltage
                                            3) calculate means and standard devations fir each of the 3 colors'
                                                extraolated stopping voltages
 

    Friday, Mar 26                Serway problems chapter 2 (11, 15, 41, 46)

    Monday, Mar 29              Photoelectric experiment due


links of the week

recent discoveries