a spectroscope cannot determine which of these about a star directly?
A surface temperature
B distance
C kinds of atoms in the star's atmosphere
D speed towards or away from Earth
the pattern and strength of lines in a spectrum of a star allows you to determine the
A velocity of the star
B temperature of the surface of the star
C chemical composition of the surface of the star
D all of the above
in order for a "visible" absorption line to occur in the hydrogen spectrum the electron must initially be in which orbital?
A the first.
B the second.
C the third.
D any allowed orbital will suffice.
electron transitions from the 2nd to the 3rd orbital in hydrogen involves which of the following?
A emission of infrared radiation.
B absorption of infrared radiation.
C emission of visible radiation.
D absorption of visible radiation.
a photon that has a Balmer line wavelength is emitted by a hydrogen atom when the electron
A jumps from the ground state to the first level above the ground state.
B jumps from the ground state to the second level above the ground state.
C falls from the third level above ground state to the second level above ground state.
D falls from the first level above ground state to the ground state.
E remains in the ground state for a sufficiently long time.
the Lyman series of ultra-violet spectral emission lines from hydrogen gas is produced by electrons jumping
A only from the first excited level to the ground state
B to the first excited level of the h atom
C to the ground state from all other energy levels
D from the continuum level, to all other levels
the chemical composition of stars can be determined because stars
A emit visible radiation
B are perfect radiators
C are far away
D are not quite perfect radiators
electron transitions between the 1st and 4th orbitals in hydrogen result in emission or absorption of which of the following?
A visible radiation.
B infrared radiation.
C ultraviolet radiation.
D you can't tell from the information given.
which one of the following is the primary difference between the observed spectra of most stars?
A the presence or absence of a continuous spectrum
B the differing strengths and patterns of the absorption lines
C the differing strengths and patterns of the emission lines
D spectra of all stars have approximately the same appearance
the Balmer series of visible spectral emissions from hydrogen gas arises f transitions in which electrons jump
A from higher levels to the first excited level
B from the second excited level to the ground state
C from higher levels to the second excited level
D from all levels to the ground state
to determine the relative abundance of two elements in a star, what must be measured for the lines of each element
A relative darkness
B width
C wavelength
D no choice
to determine what kinds of atoms the atmosphere of a planet are made of, astronomers would measure the planet's
A continuous spectrum
B spectral lines
C luminosity
D radius
which of the following are the two most abundant elements in the sun?
A hydrogen and helium
B sodium and hydrogen
C helium and iron
D iron and hydrogen
E calcium and sodium
the Balmer series of spectral lines at visible wavelengths will be emitted by a hot hydrogen gas when the electrons fall from all higher atomic energy levels to
A the next level down for each level
B the ionization level
C the ground state
D the first excited level
we can determine what elements are in the atmosphere of a star by examining
A its color.
B its absorption spectrum.
C the frequency at which it emits most energy.
D its temperature.
E its motion relative to us.
discovery of the chemical composition of the atmospheres of stars and planets is carried out by what type of study?
A relative brigntnesses
B measurement of the temperature of these objects
C the measurement of masses of these objects
D spectroscopy
dark lines in a stellar spectrum may be associated with a particular element by measuring their
A relative darkness
B width
C wavelength
D all of these
the most abundant substance in the universe is
A hydrogen
B oxygen
C silicon
D carbon
to determine what the outer regions of a star are made of, astronomers would measure the star's
A spectral absorption lines
B predominant wavelength
C actual brightness
D surface temperature
the dominant characteristic of the sun's spectrum is
A very few lines
B strong hydrogen lines
C strong molecular bands
D many lines of the heavy elements
the two most abundant elements in the sun, with the most abundant given first, are
A carbon, oxygen
B iron, hydrogen
C helium nitrogen
D hydrogen, helium
by analyzing the spectrum of a star we can determine
A which kinds of atoms are present
B the relative number of each kind of atom
C the average temperature at the surface
D all of the above
the chemical makeup of a planet's surface is usually determined
A by spectroscopy of the light emitted by the planet
B by measuring the chemical elements present in the solar wind
C by taking a sample of that surface with a space probe
D by theoretical methods, considering evolution of the planet
a detailed analysis of the spectra of stars shows that
A all stars are very large
B the light of stars comes from nuclear reactions
C complex new elements exist in stars that are not known on the Earth
D the universe is mostly hydrogen
which of the following properties of a star cannot be determined directly from its spectrum
A its chemical composition
B its temperature
C its mass
D its velocity
the two most abundant elements in the sun, in terms of its mass, are
A carbon and oxygen.
B hydrogen and oxygen.
C hydrogen and helium.
D helium and carbon.
E helium and oxygen.
the visible hydrogen lines are weak in the spectra of cool stars because m of the hydrogen atoms have their electrons in the
A fourth orbit
B third orbit
C second orbit
D ground state
which of the following quantities cannot be deduced from the spectrum of a star
A temperature
B pressure
C distance
D chemical composition
the chemical composition of a star can be found by observing
A the brightest color of the star
B the pattern of lines in the spectrum of the star
C the Doppler shift of the star
D chemical reactions occurring on the star
the observed differences between stellar spectra are caused primarily by differences in stellar
A brightness
B chemical composition
C temperature
D motions
the absorption lines in the spectrum of a star like the sun represent
A those frequencies at which the star emits particularly large numbers of photons
B those frequencies at which atoms are incapable of emitting light
C those frequencies at which atoms absorb light when their electrons jump into smaller orbits
D those frequencies at which light has been removed when it makes the electrons in atoms
jump into larger orbits
which of the following statements gives the approximate chemical composition of the sun?
A the sun is primarily iron and the elements near iron in the periodic table
B the sun is composed of about 91 percent hydrogen, about 9 percent helium and a small percentage of the heavier elements
C the most abundant element in the sun is calcium as evidenced by the strong h and k lines of singly ionized calcium in the solar spectrum
D the major contributors to the solar composition are carbon, nitrogen, oxygen and silicon
the chemical composition of a star's atmosphere may be determined by interpreting the _____ in the star's spectrum
A principal wavelength
B dark lines
C longest wavelength
D Doppler shift
the most common elements in the universe are
A large quantities of heavy elements, with smaller quantities of hydrogen an helium
B mostly hydrogen, smaller quantities of helium and very small quantities of heavier elements
C equal amounts of hydrogen and helium, with small amounts of heavier elements
D about equal amounts of all elements up to iron, but very little of any heavier elements
cool stars have weak hydrogen Balmer lines. very hot stars also have weak Balmer lines. why, in both hot and cool stars, are the Balmer lines weak
A both cool and hot stars have very little hydrogen
B in hot stars, hydrogen is not excited to the second level; in cool stars t hydrogen is mostly ionized
C in hot stars the hydrogen is mostly ionized; in cool stars the hydrogen is not excited to its
second level
the chemical makeup of a star's surface is usually determined
A by spectroscopy of the light emitted by the star
B by taking a sample of that surface with a space probe
C by theoretical methods, considering evolution of the star
D by examining the chemicals present in a meteorite
the appearance of the visible spectrum of the sun, when its light is separated into its component colors, is
A a uniform continuous spectrum with no structure
B a spectrum containing many dark absorption and many bright emission lines on a continuous background
C a spectrum consisting only of a few bright emission lines
D a continuous spectrum, crossed by thousands of dark absorption lines
if the spectrum of a main sequence star has very weak hydrogen absorption lines then
A it must not have very much hydrogen
B its surface temperature may be so low that most of the electrons in its hydrogen atoms are in the ground state
C its surface temperatures may be high enough to have excited most of the electrons in its hydrogen atoms to their second-smallest orbit
D its hydrogen is buried under the surface
hydrogen and helium together account for what percentage of the total mass of all the matter in the universe?
A about 50%
B less than 10%
C 75%
D 99%
a star moving away from the Earth will have a spectrum containing
A red shifted lines
B blue shifted lines
C unshifted lines
D weak lines
the most abundant material in the universe is
A water
B hydrogen
C carbon dioxide
D helium
weak hydrogen lines in the spectra of cool stars indicates
A there is no hydrogen in the outer atmospheres of these stars
B the temperature is not high enough to excite hydrogen atoms to the level required for these lines to appear
C these stars are very old and have entered a period of helium burning
D all the hydrogen in these stars is ionized
the most common chemical element in the universe is
A carbon
B iron
C helium
D hydrogen
which of the following cannot be determined by analyzing a star's spectrum
A surface temperature
B distance
C velocity
D surface abundances of the elements
how do astronomers know what elements such as iron are present in the sun and other stars?
A we can test samples of the sun and other stars in laboratories on Earth.
B much of the Earth is iron; therefore, much of the sun and other stars must be iron.
C the sun and other stars are more massive than Earth; therefore, they must contain heavy elements such as iron.
D dark lines are observed in the sun's spectrum that match those bright lines produced by
iron on Earth.
the pattern of spectral lines in the spectrum of a star allows one to determine
A the distance to the star
B the brightness of the star
C the chemical composition of the star at the surface
D the mass of the star
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