assuming that stars radiate like black bodies, you must know which of the following properties in order to infer the radius of a star?
A luminosity and surface temperature.
B luminosity and distance.
C luminosity and flux.
D luminosity and mass.
the apparent brightness of an object such as a star does not depend on
A how fast the star is moving across our line of sight
B the strength of the light emanating from the star
C the distance from us to the star
D the amount and kind of obstacles between us and the star
the color of a star is most directly related to its
A mass.
B surface temperature.
C central (core) temperature.
D luminosity.
E density.
which of the following properties of stars does not require a knowledge of the Earth-star distance to find it out?
A mass.
B luminosity.
C density.
D surface temperature.
E size (radius).
the luminosity of a star is a unique measure of its
A velocity of recession away from us
B temperature
C total energy output
D physical size
the luminosity of a star is
A the total energy emitted at all wavelengths towards the Earth
B equal to its apparent brightness
C the light emitted by the star within the sensitive range of the eye
D the total energy emitted at all wavelengths into all space, from its whole surface
the actual brightness of a star is a measure of
A its temperature
B its distance
C its apparent brightness
D the total number of photons it emits.
the most abundant element on the sun is
A hydrogen
B helium
C carbon
D oxygen
if the sun were twice as far away as it is now, we would receive
A twice as much flux.
B the same amount of flux.
C half as much flux.
D one-fourth as much flux.
the actual brightness of an object is a measure of
A the amount of light received at the Earth
B the total amount of light emitted by the object
C the distance of the object
D the speed of the object
what is the relation between the apparent magnitude of a star and its color?
A the apparent magnitude of a star is a direct indicator of its color.
B the apparent magnitude of a star is not an indicator of its color.
C the answer depends on what time of night the star is observed.
D the relationship is not fully known.
a measurement of a star's flux tells us directly the
A star's distance from the Earth.
B star's total energy output compared to the sun's.
C star's surface temperature.
D rate at which energy reaches the Earth.
E rate at which energy leaves the star.
the temperature of a star determines its
A color
B radius
C mass
D luminosity
the average temperature of that part of the sun which we see is
A 6000 k
B 60,000 k
C 600 k
D no choice
the difference between a star's actual brightness and apparent brightness is a measure of its
A distance
B brightness
C temperature
D luminosity
the most fundamental property of a star is its
A temperature
B luminosity
C mass
D diameter
the actual brightness of a star is related to
A the number of light waves emitted by the star every second
B the distance of the star
C the color of the star
D the number of light waves which reach Earth every second
stellar surface temperatures range from
A 5,000-6,000 f
B 4,000-10,000 f
C 4,000-100,000 f
D 100-100,000 f
if two stars have the same size but different temperatures, then the hotter star will be
A bluer and brighter
B redder and brighter
C bluer and fainter
D redder and fainter
the most fundamental of all stellar properties is
A radius
B mass
C temperature
D luminosity
suppose you observe a previously unstudied star and find its apparent brightness. to determine its actual brightness, you need to find its
A distance
B color
C temperature
D brightness as seen from Earth
which of the following observed quantities depends upon the distance to the object
A Doppler shift
B color
C actual brightness
D apparent brightness
about what fraction of stars are multiple star systems?
A 10%
B 50%
C 90%
D no choice
the reason astronomers use the concept of the actual brightness is to
A make life difficult for introductory astronomy students!
B allow stars to be compared with the effects of differing distance removed
C allow stars to be compared with the effects of differing mass removed
D allow stars to be compared with the effects of differing temperature removed
if two stars in the sky have the same apparent brightness and are not hidden by gas or dust clouds, then
A they have the same temperature
B they must be at the same distance away from us
C the furthest one has the greatest luminosity
D they have the same angular size
which of the following stars is hottest
A a red giant
B a white dwarf
C the sun
D a star detectable only in the infrared
the actual brightness of a star is a measure of
A the total light output of the star
B the distance of the star
C the size of the star
D the age of the star
the actual brightness of the sun, as compared to the range of actual brightness possible for stars, is
A large
B about average
C small
D on a completely different scale
to obtain a star's actual brightness, we generally need its apparent brightness and its
A mass
B central (core) temperature
C Doppler shift
D distance
if two stars have the same size but different temperatures, then the hotter star will be
A bluer and brighter.
B redder and brighter.
C bluer and fainter.
D redder and fainter.
which of the following represents the approximate range of stellar masses?
A all stars have the same mass
B 1.0 to 10 solar masses
C 0.1 to 5 solar masses
D 0.05 to 50 solar masses
the actual brightness of an object is a measure of
A how bright it appears in the sky
B how far away it is
C how old it is
D how much light it emits
a star's actual brightness is a measure of its
A distance
B size
C total energy output
D no choice
which of the following spectra originates from the hottest star?
A a
B b
C g
D m
the sun is closest to which type star?
A a
B b
C g
D m
if the following spectral types refer to stars on the main sequence, which is the most massive
A a
B b
C g
D k?
if one wanted to test a new ultraviolet detector, what type of star should one look at
A a
B b
C g
D k?
a nova is a star undergoing
A regular pulsation
B a surface explosion
C a catastrophic explosion
D an invisible explosion in the core
the cause of a nova outburst is thought to be
A the exhaustion of the nuclear fuel
B the beginning of helium burning
C gravitational implosion
D the addition of hydrogen to a star contracting toward the white dwarf stage.
which of the following spectra originates from the reddest star?
A a
B b
C g
D m
which type of variable star is most useful as a distance indicator when seen individually
A eclipsing
B novae
C cepheid
D supernovae
which of the following stars is the "brightest" (magnitudes are given)
A 1
B 5
C -1
D 3
the difference between a star's b magnitude and its v magnitude is a measure of its
A brightness
B color
C distance
D no choice
evidence for the interstellar medium is that
A distant stars are reddened
B distant stars have large Doppler shifts
C most apparently bright stars are relatively far from us
D over a long period of time, stars slow down due to friction
the presence of planets around another star may have been detected by
A directly observing the planets through an extremely large telescope
B "listening" to intelligent radio signals from the vicinity of a nearby star
C measuring the Doppler effect of the planet
D noticing a wobble in the motion of a nearby star
a star has a parallax of 0.1 seconds of arc and an apparent brightness of .7. what is the absolute magnitude?
A 0.47
B 10.0
C 4.7
D 47.0
which of the following stars are observed to change their visible brightness most dramatically
A novae
B red giants
C cepheid variables
D stars near the upper end of the main sequence
which of the following is the most regular pulsating variable star
A cepheid
B red giant
C pulsar
D eclipsing binary
the mass-luminosity relation applies
A only to main-sequence stars
B only to young stars
C to all stars
D no choice
one would be most likely to find absorption bands due to molecules in a spectrum of type
A a
B b
C g
D m
which of the following types of variable stars is not a pulsating variable
A classical cepheid
B w Virginia
C RR Lyrae
D supernova
which type of variable star is a member of a binary system undergoing a surface explosion
A eclipsing
B novae
C cepheid
D supernovae
which of the following variable stars exhibit the greatest change in visible light
A cepheid
B red giant
C nova
D supernova?
of the following variable stars, which does not change its size or temperature
A cepheid
B red giant
C novae
D eclipsing binary
the actual brightness of a star is measured by its
A absolute magnitude
B apparent magnitude
C bolometric magnitude
D visual magnitude
which of the following is not true of novae
A they can increase in brightness by as much as a 1000
B only a minor surface explosion is involved
C they are thought to occur only in binary stars
D they can occur only once in a given star?
which of the following is not true of cepheid variables
A the light variation is periodic
B they are useful for determining astronomical distances
C they occupy a restricted region of the H-R diagram
D the change in brightness from minimum to maximum may be as much as a factor of 100
which of the following spectra has the fewest absorption lines?
A a
B b
C g
D m
the proper motion of a star is a measure of its
A distance
B motion through space
C brightness
D no choice
which of the following variable stars is rarest
A cepheid
B red giant
C nova
D supernova
planets around stars other than the sun
A can be seen directly
B have definitely been observed indirectly as a wobble in the star's motion
C may be detectable indirectly as a wobble in the star's motion
D will never be detected, probably do not exist, and are outside the realm of science
for measuring parallax and proper motion of a star, the reference system used is
A a background of bright stars
B a background of faint stars or galaxies
C a background of gaseous nebulae
D no choice
which of the following variables is rarest
A cepheids
B red giants
C novae
D supernovae
Return to Table of Contents