Week 7 Feb. 16

We are discussing photoelectric effect and will be moving on to other photon processes (chs 8, 9)

If a photon gets scattered by an atom in the vacuum (absorbed and reemitted), but no one observes the event, did an event occur?
Wrong question, --what is a photon? What is an Atom? What is an observation?

Ch 7--problems 1, 2, 7, 9, 15    Wed. Feb. 25

Ch. 8 --problems 2,4, 5, 7, 14 (you should ask lots of questions on 14), 17, and 25. Wed. March 4

Ch. 9     4, 13, 15, 16, 27 Wed. March 11 (Test 2 on Friday 20th)

Think about a data set like this. YOU WILL SEE SUCH A THING A FEW TIMES!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Below is some data that is relevant to using the photoelectric effect and using that to determine Planck's constant. The numbers might be slightly off here (experiment). I am not assigning this as HW--but am telling you that you must know how to do this 1, 2, 3 times. You should be able to wisely and correctly select data and then formulate a line that gives you both Planck's constant and the workfunction for the material. For determining "the line" there are only two possible and usable data points in the table below. Before crunching math (a straight line--no big deal), you better know how to select the correct data. You should be able to explain why you selected that particular data. You should be able to take an appropriate data point and determine KE(max).

Data Point	Retarding Potential magnitude(Volts)	Photocurrent (nA)	Wavelength
1	1.32994	0.0000	440nm
2	1.27083	0.0000	440nm
3	1.23361	-0.0002	440nm
4	0.6304	-2.6410	440nm
5	0.3578	-2.9538	440nm
5	1.43345	0.0000	500nm
6	0.98475	0.0000	500nm
7	0.97332	-0.0001	500nm
8	0.4924	-1.7637	500nm
9	0.2451	-3.1559	500nm
10	0.75886	0.0000	550nm
11	0.3764	-1.7673	550nm
12	0.66065	0.0000	575nm
13	0.57062	0.0000	600nm
14	0.2703	-0.81432	600nm
15	0.62349	0.0000	660nm
16	0.40135	0.0000	660nm
17	0.40129	-0.0002	660nm
18	0.2105	-0.40743	660nm