Issued Wed, Feb 21 Due Wed, Feb 28

Required reading: F+T Ch. 2, and 3.1-3.3 (Beiser Ch. 3.6-3.9, 5.1)

Reminder: Evening exam, Thursday Feb 22, 7:30-9, in Muen E417

1) F+T 2-10 (a and b only)

2) F+T 2-12a

3) F+T 2-14

4) F+T 2-16

5a) A beam of neutrons that emerges from a nuclear reactor contains neutrons with a variety of energies. To obtain neutrons with an energy of 0.050 eV, the beam is passed through a crystal whose atoms are 0.20 nm apart. At what angles relative to the original beam will the desired neutrons be diffracted?

5b) Although we didn't worry about it, the energy of electrons entering a crystal changes due to the work function of the metal. (Does it increase or decrease?) Consider a beam of 44 eV electrons directed at a nickel target. Suppose the work function of nickel is 26 eV. Compare the respective de Broglie wavelength of the electron inside and outside the crystal. (Do you think that a proper theoretical treatment of the Davisson-Germer experiment should take this effect into accout?)