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http://www.astronomynotes.com/light/discretc.gif. Suppose two observers look at the spectrum of a cloud of gas in a laboratory; the first reports seeing emission lines and the second reports absorption lines. Explain. 1) Only the first observer sees the gas against a hot background
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Suppose two observers look at the spectrum of a cloud of gas in a laboratory; the first reports seeing emission lines and the second reports absorption lines. Explain. 1) Only the first observer sees the gas against a hot background 2) Only the second observer sees the gas against a hot background. 3) One observer is moving rapidly relative to the other. 4) The atoms in the gas are forming molecules.
http://upload.wikimedia.org/wikipedia/commons/thumb/b/b2/Hydrogen_transitions.svg/2000px-Hydrogen_transitions.svg.pnghttp://upload.wikimedia.org/wikipedia/commons/thumb/b/b2/Hydrogen_transitions.svg/2000px-Hydrogen_transitions.svg.png
656 nm 486 nm 434 nm 410 nm
656 nm: red-orange 486 nm: blue 434 nm: indigo 410 nm: violet
Atoms of different elements have unique spectral lines because each element 1) has atoms of a unique color. 2) has a unique set of neutrons. 3) has a unique set of electron orbits. 4) has unique photons.
Atoms have particular associated spectral lines because 1) electrons have only certain allowed orbits. 2) light consists of waves. 3) light waves can show the Doppler effect. 4) speed of light in a vacuum is a constant.
In the Sun, the transition from level 4 to level 2 of hydrogen produces photons with a wavelength of 486.1nm. In a star twice as hot as the Sun, this transition would produce photons with 1) half that wavelength. 2) the same wavelength. 3) twice that wavelength. 4) four times that wavelength.
Here is the spectrum of a mystery star: Which elements are present? Calcium only Calcium and hydrogen Magnesium and calcium Calcium, hydrogen, and magnesium
Here is the spectrum of a mystery star: Which elements are present? Calcium only Calcium and hydrogen Magnesium and hydrogen Calcium, hydrogen, and magnesium
Decoding Cosmic Spectra http://www.pbs.org/wgbh/nova/space/decoding-cosmic-spectra.html
Here is the spectrum of a mystery star: Which elements are present? Calcium, hydrogen, and magnesium Calcium and hydrogen Magnesium and hydrogen All of them
Origins: Decoding Spectra of Light from Distant Galaxies Origins Hour 4, Back to the Beginning, Chapter 6 http://www.pbs.org/wgbh/nova/programs/ht/qt/3114_06.html