Rec10_172Fall11_rl - constituents of the material? Explain...

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Physics 172 – Recitation 10 Fall 2011 Purpose: The purpose of this recitation is to allow you to gain further experience working with the Energy Principle as applied to energy quantization. Readings: Sections 8.1-8.6 General Instructions: Identify your system State which objects are interacting with the system State the fundamental principle(s) you use to solve the problems Draw an appropriate diagram labeling key features of the problem State the approximations and simplifying assumptions you use. Problem 1. A certain material is kept at a very low temperature. It is observed that when photons with energies between 0.2 and 0.9 eV strike the material only photons with energies 0.4 and 0.7 eV are absorbed. a) What can you conclude about the internal energy states of the microscopic
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Unformatted text preview: constituents of the material? Explain briefly. b) The material is warmed up so that it starts to emit photons. When it has been warmed up enough that it begins to emit 0.7 eV photons what other photon energies are observed to be emitted by the material? Explain briefly. Checkpoint 1 Problem 2. We have reason to believe that a certain kind of microscopic system has only three quantum states. When we excite a collection of them we observe that they emit photons of three different energies: 2.48 eV, 1.91 eV and 0.57 eV. a) Propose two possible energy-level schemes for this system. b) Explain how measurements of photons absorbed by a cold collection of these systems can be used to distinguish between your proposed schemes. Checkpoint 2...
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This note was uploaded on 12/07/2011 for the course PHYS 172 taught by Professor ? during the Fall '08 term at Purdue University-West Lafayette.

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