Thursday, August 2, 2012

A few more example problems

on quantum/atomic physics. I should be able to post some more tomorrow evening, but these are highly relevant for the exam.

8 comments:

Anonymous said...

Can you post solutions to the Sum 09 Aug 5 hw9?

Anonymous said...

Will there be any questions on the uncertainty principle or binding energy?

Anonymous said...

Do we need to know the difference between converging lens and diverging lens.? As in the different problems of those?

pleclair said...

1) There are many requests for solutions to old problems. I'll be perfectly honest, I'm tied up until at least 6pm tonight. It won't happen until then, and I'm not sure I can do it for all the requests. I'll see what I can do.

2) No.

3) Yes, you'll need to know the characteristics of converging and diverging lenses - what sorts of images form at what distances relative to the focal length, etc.

Anonymous said...

Will there be any questions involving prisms about angular dispersion of the visible light?

pleclair said...

No prisms or angular dispersion.

Anonymous said...

For #3 how did you get the final answers? I did hc/E to solve for the wavelengths and didn't get the right answer.

For #4 The question asks for wavelengths but the answers are just changes in energy. Would that be the final answer or would we need to solve for the wavelengths using those Es?

Thank you!

pleclair said...

#3 - watch the units, if the energy is in eV, you'll need to convert it to J or use Planck's constant in eV*s instead of J.s. Also the wavelength units, nm=1e-9. A handy relationship is that hc=1240eV*nm, so if you want wavelengths in nm and have energies in eV, you can just do (lambda) = 1240/(energy in eV).

#4 - exactly, I found the energy differences, which is just an intermediate step. The wavelengths (which would be the final answer) you'd get like above: (lambda in nm) = 1240/(energy diff in eV).