Astronomy Online Ch 4 HSU – Flashcards
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A blackbody is a idealized object in physics and astronomy which
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Refracts no light and emits light in a manner determined by the temperature
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A scientist reports that his measurements of the temperature of the surface of a newly discovered planet is -20K. What conclusion can you draw from this report
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The result is erroneous since one cannot have negative absolute temperature.
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According to Kirchhoff's Laws, the continuous spectrum of light from a hot star, after passing through a cool gas cloud
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will show absorption features when light has beed absorbed by the storms of the cool gas
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An astronomer finds a source of light in space which emits light only in specific, narrow emission limit. Kirchhoff's laws lead him to what conclusion
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The source is made up of hot, low-density gas
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An example of an object which emits no radiation at all is
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Any object at a temperature of 0K
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Compared to the mass of an electron, the mass of a proton is
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almost 2000 times greater
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How many electrons will surround the nucleus of a neutral atom of the isotope 18O of Oxygen
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8
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In Bohr's model of the hydrogen atom, light is emitted whenever
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an electron jumps from an upper to a lower energy level or orbit
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Isotopes of a particular element in the periodic table have which nuclear property in common?
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The same number of protons but different numbers of neutrons in the nucleus
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On the absolute Kelvin temperature scale, the temperature of freezing water is about
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-273K
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Pieces of metal are heated by varying amounts in a flame. The hottest of these will be the one that shows which color most predominantly
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blue
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The Doppler effect is the change in the wavelength of light caused by the source
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Moving with respect to the observer
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The atom consists of
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negatively charged electrons moving around a very small but massive, positively charge nucleus
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The chemical makeup of a star's surface is usually inferred
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by spectroscopy of the light emitted by the star
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The isotope 15N has an atomic number of 7. the nucleus of the isotope contains
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7 protons and 8 neutrons
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The majority of the mass of ordinary matter resides in
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the nuclei of the atoms
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The normal temperature of the melting point of water ice is
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273K
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The person who discovered the atomic nucleus was
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Sir Earnest Rutherford
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The property of a neutral atom which defines its chemical behavior and fixes its position in the periodic table is
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the number of protons in the nucleus
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The range of temperatures in the Kelvin (absolute) scale between the freezing point and boiling point of water is
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100 degrees
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The series of spectral absorption lines in the inferred part of the spectrum, known as the Paschen series, results from atomic transitions in hydrogen atoms in which electrons are lifted from which energy level to all higher atomic energy levels.
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the n = 3 level
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The spectrum of sunlight, when spread out by a spectrograph, has what characteristic appearance
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A continous band of color, crossed by innumerable dark absorption lines.
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The temperature of boiling water at ordinary pressures on the absolute scale, Kelvin, is
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373K
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When a rod of metal is heated intensely, its predominant color will
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change from red, through brand to white, and then to blue
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Where does the Paschen series of spectral lines from hydrogen gas appear in the electromagnetic spectrum?
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In the inferred, with wavelengths longer than 700 nm
