# Physics H133: Problem Set #9

Here are some hints, suggestions, and comments on the problem set.
## Two-Minute Problems

Remember to give a **good** explanation, no longer than
two sentences.

- Q10T.2: How are kinetic energy and wavelength related? de Broglie!
- Q10T.4: Check the derivation in Section Q10.3 (the summary
in the chapter overview at the beginning may be clearest!).

## Chapter Q9 and Q10 Problems

- Q10S.4 and Q10S.5: Follow the usual step -- take two derivatives,
plug everything into the Schrodinger equation and check whether
the ansatz solves the equation. In one case it does, in one it doesn't.
- Q10S.8: (a) Where does a cosine "crest"? (b,c) Straightforward if you
use some graph paper. (d) Remember how to compute the local wavelength
(see Section Q10.2).
- Q10R.1: Parts (a), (b), and (d) are straightforward. For (c),
check how the kinetic energy is found at each x and how this relates
to the local momentum and thus wavelength. Figure Q10.1 may be helpful.
For (e), guess some power of n (not necessarily an integer!).
- Q9A.1: Just follow the instructions (and hint) in each part.

Your comments and
suggestions are appreciated.

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**Physics H133: Hints for Problem Set 9.**

Last modified: 05:20 pm, April 15, 2012.

furnstahl.1@osu.edu