# Ch7 HW3 - Ch7 HW3

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Ch7 HW3 (Homework) BRANDON JARROTT FELDKAMP PHYS 2211, section M, Fall 2008 Instructor: Jennifer Curtis Web Assign Current Score: 21 out of 21 Due: Wednesday, November 26, 2008 09:00 AM EST Description Vibrational energy levels; other quantized systems. Instructions Reading: Sections 7.4-7.8 The due date for this assignment is past. Your work can be viewed below, but no changes can be made. 1. [MI2 07.X.06.alt01] 2/2 points The Franck-Hertz experiment involved shooting electrons into a low-density gas of mercury atoms and observing discrete amounts of kinetic energy loss by the electrons. Suppose instead a similar experiment is done with a very cold gas of atomic hydrogen, so that all of the hydrogen atoms are initially in the ground state. If the kinetic energy of an electron is 11.2 eV just before it collides with a hydrogen atom, how much kinetic energy will the electron have just after it collides with and excites the hydrogen atom? K final = 1 1 eV Solution or Explanation The ground electronic state of hydrogen is -13.6 eV. The first excited state is -3.4 eV. The electron will lose [-3.4 - (-13.6)] = 10.2 eV if it excites the hydrogen atom. The final kinetic energy of the electron is this much less than its initial kinetic energy. Note that the electron doesn't have enough initial kinetic energy to excite the second excited state of hydrogen. 2. [MI2 07.X.09] 3/3 points Suppose a collection of quantum harmonic oscillators occupies the lowest 4 energy levels, and the spacing between levels is 0.05 eV. What is the complete emission spectrum for this system? That is, what photon energies will appear in the emissions? Include all energies, whether or not they fall

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## This note was uploaded on 02/21/2010 for the course PHYS 2211 taught by Professor Prog during the Spring '09 term at Georgia Institute of Technology.

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Ch7 HW3 - Ch7 HW3

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