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18 Cards in this Set
- Front
- Back
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why can a good blacksmith judge the temperature of a piece of heated iron by its color?
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hot objects emit more black body radiation
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why do hot starts look bluer than cold stars
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hotter objects emit more blue
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use black body radiation to explain why you can light a cig with a match but not a bonfire
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?????
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difference b/w a neutral atom, and ion, and an excited atom?
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-ion-atom that has lost 1+ electrons
-excited atom-move electron in atom to higher energy level |
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how do energy levels in an atom determine which wavelength photons it can absorb or emit?
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atom drops from high to low energy level, emits photons. ?????
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what spectrum would you record observing molten lava? through glasses?
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continuous spectrum, w/ absorption lines caused by gases above.
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why does the strength of the Balmer lines depend on the temp. of the star?
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measure only absorption lines in 2nd energy level. cool stars have fewer violent collisions, excited atoms.
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why does a stellar spectrum tell us about the surface layers but not the deeper layers of the star?
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?????
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why do we not see TiO bands in the spectra of hot stars?
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Absorption bands due to the molecule titanium dioxide (TiO). They are prominent in the spectra of K stars and M stars, which are cool enough for TiO to survive.
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if no visible lines of element in star, is element not present?
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star can be too hot or cold to produce certain lines of elements
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if star moves directly perpendicular to a line connecting to earth, will dopler effect change its spectrum?
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no, doppler effect can not be used to measure perp. lines
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why would we expect star that rotates rapidly to have broad spectral lines? what else could broaden lines?
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yes, motion smears spectral line. collision broadening smears spectral lines too. colliding atoms realease dif. levels of energy.
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human body temp. is 310K, at what wavelength do humans radiate the most energy? what kind of radiation?
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=3,000,000/T=9677.42
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star w/ surface temp. of 20000k, what wavelength will it radiate most energy?
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3,000,000/20000=
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IR observations show that star is most intense at 2000 nm. what is temp. of star's surface?
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3000000/2000=
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double black body temp. by what factor will total energy radiated per second per sq. meter increase?
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??????
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star w/ temp. 6000 K, other star w/ temp. 7000 K, how much more energy/second will hotter star radiate from each sq. meter of its surface?
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62,653,500
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transition A produces light w/ wavelength 500 nm. transition B involves 2x as much energy. what wavelength light does it produce?
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i have no fucking clue
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