Davisson and Germer used a nickel crystal for their scattering ...

[tatyanajohnson]

Davisson and Germer used a nickel crystal for their scattering experiments that had been modified when they tried to repair it. Which of the following describes the major change from before they tried to repair it and afterward that allowed them to work on the groundbreaking experiments they did?
  A. The oxidation of the nickel from immediately after it was taken from a vacuum environment introduced impurities with intermediate band gaps.
  B. The heating processes created larger crystals, which allowed them to clearly see the electron diffraction.
  C. Under the intense heat of their repair process, the electrons were scattered off of energetically oscillating nickel atoms, whereas before they hit the stationary lattice atoms.
  D. Their knowledge of the new nickel crystals led them to believe that electrons with low energy (on the order of 10 eV) only would scatter off of the closely spaced nickel atoms.

Question 2

When de Broglie's matter waves are applied to electrons in the Bohr atom, which of the following occurs?
 

A. The electron is found to have in its orbit an integral number of half-wavelengths.
  B. Bohr's quantization assumption for electron orbits is modified to incorporate the wave properties of the electron.
  C. de Broglie's results allow an integral number of wavelengths in the electron orbits.
  D. The angular momentum of the electron in the atom is constant, with longer wavelengths at larger quantum numbers.

[cpetit11]

Answer to Question 1

B.
The larger crystals that formed were more orderly than the fewer small crystals previously in the nickel structure. This allowed Davisson and Germer to clearly see the electron scattering patterns inherent to the large crystals.

Answer to Question 2

C,
The de Broglie wavelength of the electron orbiting the nucleus is quantized in the same way that Bohr's atom is quantized. An integral number of electron wavelengths is found in each electron orbit.

[tatyanajohnson]

Excellent

[mochi09]

Gracias!