CH4171-CH7 components of optical instruments with concept tests

CH4171-CH7 components of optical instruments with concept tests

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Unformatted text preview: CH 7 Homework 1. Use the Wein displacement law to calculate the wavelength emitted by a blackbody that has been heated to 5000 K. 2. Use Stefan’s law to calculate the total energy output in W/m 2 for the blackbody radiator in Q1. 3. How many lines per millimeter in a grating would be required for the first-order diffraction line for l = 400 nm to be observed at a reflection angle of 5 degrees when the angle of incidence is 45 degrees. 4. A monochromator has a focal length of 1.6 m and a collimating mirror with diameter of 3.5 cm. The dispersing device was a grating with 1500 lines/mm. For first-order diffraction, what is the resolving power of the monochromator if a collimated beam illuminated 3.0 cm of the grating? 5. What length of mirror drive in a Michelson interferometer is required to produce a resolution sufficient to separate IR peaks at 4002.1 and 4008.8 cm-1 ? Due Wed 9/21 CH 7 Components of Optical Instruments Instruments for measuring absorption, fluorescence, phosphorescence, and scattering contain similar components. 1. Source of light 2. Sample holder 3. Spectral isolator 4. Detector 5. Display Sources of Radiation Xe Lamp Tungsten Lamp Nernst Glower Hollow Cathode Lamp Wavelength, nm 200 400 700 1000 2000 20,000 40,000 UV Visible Near IR IR Far IR LASERS { Line Sources { Continuum Sources Sources of Radiation Xe arc lamp used in IMAX theaters Sources of Radiation Invented by Nernst in 1897 and made out of a ceramic that wouldn’t oxidized as it was heated so it didn’t need a bulb. SiC now used. Blackbody Radiators Sources of Radiation Blackbody Radiation EM radiation is produced any time electric charges oscillate. At any non-zero temperature, the atoms, molecules, and electrons are oscillating. At any non-zero temperature, all matter will emit EM radiation. Power P = σε AT 4 λ T = 2.898 x 10-3 m K Wein’s Displacement Law σ is the Stefan-Boltzmann constant: 5.6703 x 10-8 W/m 2 K 4 ε is emissivity of the object; between 0 and 1; 1 for a true blackbody A is area T is temperature Stefan’s Law Sources of Radiation Blackbody Radiation Sources of Radiation Concept Te$t In 1965, microwave radiation peaking at a wavelength of 1070 um was discovered coming in all directions from space. This background radiation is believed to be left over from 15 billion years ago, soon after the universe formed. Which temperature does this radiation correspond? (A) 0 K (B) 2.79 x 10-6 K (C) 2.7 K (C) 2.7 K LASERS Concept Te$t Which of the following is true of “normal” fluorescence (non-stimulated or spontaneous) light emission? (A) Emitted photons are incoherent (B) Emitted photons are highly collimated (C) Emitted photons are higher in E than absorbed photons (D) Both A and B are true (A) Emitted photons are incoherent Waves emitted during fluorescence are not in phase with each other as they travel. Concept Te$t Which of the following statements represents an accurate comparison of 2-level vs. 3-level lasers?...
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This note was uploaded on 11/16/2011 for the course CHEM 4171 at Colorado.

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CH4171-CH7 components of optical instruments with concept tests

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