Due Wed, Feb. 15

Required reading for this week: F+T Chapter 2

(Optional: Beiser, Ch. 3.1-3.5)

Reminder- 1st midterm: Thur. evening, Feb. 16, 7:30-9 Muen E-131.

(Any possible conflicts must be discussed with me BEFORE Feb 10!)

HW problems:

1. The wavelength of the x-ray line for a certain element is 1.94 Angstroms. What is the element?

2. F+T 1-21

3. F+T 1-26

4a) F+T 2-5

b) Find the kinetic energy of an electron whose de Broglie wavelength is the same as that of a 200 keV x-ray.

5a) What are the phase and group velocities of the deBroglie waves of the electron in problem 4b?

Note: (If you cannot solve problem 4b, use a value of kinetic energy of the electron = 40 keV)

b) The phase velocity of ripples on a liquid surface is , where S is surface tension, is the density of the liquid, and is (as usual) the wavelength of the ripples. Find the group velocity of the ripples. (Express you answer in terms of the phase velocity)