astro5
Terms
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- blue
- If a star is moving toward us, its light will be Doppler shifted toward the:
- blue, yellow, red
- Three stars of different colors all have the same absolute magnitude. Arrange them in order of increasing size:
- black
- A body which is a perfect radiator is also referred to as a __ body:
- kelvin
- The total energy emitted per unit area by a black body is proportional to the fourth power of the ___ temperature:
- is moving toward us
- If the wavelengths of the absorption lines in a star are shorter than the wavelengths of the corresponding absorption lines observed in the Sun, that star:
- the fourth power of its temperature
- The energy per unit area of continuous radiation emitted by a star is proportional to:
- difference in the energies of the two levels
- The wavelength of light emitted by an excited atom depends upon the:
- the Balmer series
- The visible set of lines produced by hydrogen transitions ending on the n = 2 level is called:
- speed up
- As a gas is heated, its toms or molecues:
- electrons
- The Bohr model of the atom puts the __ in shells around the nucleus:
- a small nucleus of protons and neutrons, surrounded by a cloud of electrons
- An atom can best be described as:
- the nucleus
- The protons in an atom are found in:
- absolute magnitudes
- If two stars have the same spectral class and are of different sizes, they must have different:
- temperature
- the average speed of the molecules of a gas is directly related to the ____ of the gas:
- slow down
- As a gas is slightly cooled, its atoms or molecules:
- Wrong - each spectral class represents a range of temperatures. The temperature is determined by spectral lines
- Each spectral class of stars represents a unique temperature. :
- the radiation it emits tells us nothing about its chemical composition
- A body which is a perfect radiator is reffered to as a black body. This is because:
- in a cloud around the nucleus
- The electrons in an atom are found:
- the stefan-boltzmann
- "The total energy emitted per unit area per unit time for a perfect radiator is proportional to the fourth power of the temperature in degrees Kelvin." This is a statement of _____ law. :
- 2,3
- The hydrogen alpha line involves transitions between n = _____ and the n = _____ levels of hydrogen:
- fourth
- The total energy emitted per unit area by a black body is proportional to the ___ power of the Kelvin temperature:
- sizes
- If two stars of the same spectral class have different absolute magnitudes, they must have different:
- is the change in observed wavelength from a wave source that is approaching or receding from us
- the doppler effect
- red
- If a star is moving away from us, its light will be Doppler shifted toward the: