Lec10-Feb18[1]

Lec10-Feb18[1] - 2/18/11 Quiz QuesNon #1 When an electron...

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Unformatted text preview: 2/18/11 Quiz QuesNon #1 When an electron jumps from a higher energy level to a lower energy level in an atom, what happens? Astro 109 Lecture 10: Light and Atoms Feb. 18 A. B. C. D. A photon of light is emiFed. A photon of light is absorbed. The atom's temperature changes. The atom changes color. Feb. 18 Quiz QuesNon #2 How does the Doppler effect change the emission line spectrum of an object moving toward you? A. B. C. D. E. The emission lines get brighter. The emission lines get fainter. The emission lines shiR to longer wavelengths. The emission lines shiR to shorter wavelengths. The spectrum does not change. Key Concepts emission line and absorpNon line spectra atomic structure spectral lines <--> composiNon of a gas Doppler effect Feb. 18 Feb. 18 Kirchhoff's laws Structure of maFer Feb. 18 Feb. 18 1 2/18/11 Bohr model for hydrogen Energy level transiNons not allowed energy levels are "quanNzed" allowed Feb. 18 Feb. 18 ConnecNon to light photon = "par+cle" of light E = h = hc jump down = emit light jump up = absorb light Feb. 18 Feb. 18 Chemical fingerprinNng Discussion QuesNon What is the main reason that different chemical elements produce different emission line spectra? Different elements have different A. B. C. D. E. sizes boiling points responses to heat arrangements of electron energy levels smells Each atom or molecule has a unique set of spectral lines. Feb. 18 Feb. 18 2 2/18/11 Chemical fingerprinNng Spectrum of the Sun By idenNfying lines, we can determine the chemical composiNon of a gas. Feb. 18 Feb. 18 Discussion QuesNon How does a conNnuous (blackbody) spectrum change with temperature? A. Higher temperature shiRs the spectrum toward the red. B. Higher temperature shiRs the spectrum toward the blue. C. Temperature does not affect the spectrum. Discussion QuesNon How does an emission line spectrum change with temperature? A. Higher temperature shiRs the spectral lines toward the red. B. Higher temperature shiRs the spectral lines toward the blue. C. Temperature does not affect the spectral line locaNons. Feb. 18 Feb. 18 Train staNonary The Doppler Effect Feb. 18 Feb. 18 3 2/18/11 Train moving to the right Discussion QuesNon When I swing the Doppler ball around my head, what do I hear? A. B. C. D. the standard pitch a pitch higher than the standard pitch a pitch lower than the standard pitch a pitch that oscillates higher and lower than the standard pitch E. nothing at all Feb. 18 Feb. 18 Light source moving to the right Discussion QuesNon If I were to swing the hydrogen lamp around like the Doppler ball, what would you see through the diffracNon graNng? A. B. C. D. A conNnuous spectrum. The emission lines would always shiR slightly to the red. The emission lines would always shiR slightly to the blue. The lines would shiR to the red when the lamp is moving toward you, and to the blue when it is moving away. E. The lines would shiR to the blue when the lamp is moving toward you, and to the red when it is moving away. Feb. 18 Feb. 18 Here is the laboratory spectrum of an object. On measuring moNon Discussion QuesNon (A) Which of these spectra corresponds to the same object seen moving away the fastest? (B) (C) We can only measure the component of moNon along the line of sight. Feb. 18 (D) Feb. 18 4 2/18/11 Doppler effect and rotaNon HW #1 How do electrons in an atom change energy? A. An electron can only gain energy and leave an atom. B. An electron can only move between discrete energy levels, but can never leave the atom. C. An electron can only move between discrete energy leaves, or escape the atom (if given enough energy). D. An electron can change to any other value of energy within the atom, but can never escape. E. An electron can change to any other value of energy, or escape the atom. Feb. 18 Feb. 18 HW #2 When an electron jumps from a higher energy level to a lower energy level in an atom, what happens? A. B. C. D. E. A photon of light is emiFed. A photon of light is absorbed. The atom's temperature changes. The atom changes color. None of the above. HW #3 How does the Doppler effect change the emission line spectrum of an object moving toward you? A. B. C. D. E. The emission lines get brighter. The emission lines get fainter. The emission lines move to longer wavelengths. The emission lines move to shorter wavelengths. The spectrum does not change. Feb. 18 Feb. 18 HW #4 You are given a traffic Ncket for running a red light (wavelength 700 nm). You tell the police officer that because you were approaching the light, the Doppler effect made the light appear green (wavelength 500 nm). How fast would you have had to be going for this to be true? A. B. C. D. E. Feb. 18 Doppler shiR of a stoplight 0 obs 0 v = 700 nm (red) = 500 nm (green) = 200 nm = v c 1000 km/hr 30,000 km/hr 1 million km/hr 10 million km/hr 300 million km/hr Feb. 18 = 3.0 105 km s-1 = 8.6 104 km s-1 = 86, 000 km s-1 = 309 million km/hr = 190 million mph 200 nm 700 nm 5 ...
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This note was uploaded on 03/24/2011 for the course PHYS 123 taught by Professor Wenkstern during the Spring '08 term at Rutgers.

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