chapter 24 study guide
A star that is 5 units of magnitude brighter than another is [2.5/5.0/100] times brighter
100
The first naked-eye supernova in 383 years occurred in the southern sky in [1965/1973/1987].
1987
A graph showing the relation between the true brightness and temperature of stars is called a(n)
H-R diagram
Binary stars can be used to determine stellar a) mass c) brightness b) temperature d) distance e) composition
a
In the cores of incredibly hot red giant stars, nuclear reactions convert helium to a) carbon c) oxygen e) nitrogen b) hydrogen d) argon
a
Matter that is pulled into a black hole should become very hot and emit before being engulfed. a) X-rays c) atoms e) infrared radiation b) hydrogen nuclei d) degenerate matter
a
The most abundant gas in dark, cool, interstellar clouds in the neighborhood of the Milky Way is a) hydrogen c) helium e) nitrogen b) argon d) oxygen
a
Which one of the following is NOT a type of galaxy? a) nebular c) spiral b) irregular d) elliptical
a
Which one of the following stars would appear brightest in the night sky? a) Sirius c) Alpha Centauri e) Betelgeuse b) Deneb d) Arcturus
a
By determining the light period of a cepheid variable, its (color/size/absolute magnitude) can be determined.
absolute magnitude
The brightness of a star, if it were viewed at a distance of 32.6 light-years, is called its
absolute magnitude
A star's brightness as it appears when viewed from Earth is referred to as its
apparent magnitude
there [are/are no] stars with negative magnitudes.
are
Planetary nebulae are the cast-off outer [planets/atmospheres] of collapsing red giants that formed from medium-mass stars.
atmosphere
An interstellar accumulation of dust and gases is referred to as a a) red giant c) white dwarf b) nebula d) galaxy e) neutron star
b
On an H-R diagram, about 90 percent of the stars are a) giants c) white dwarfs b) main-sequence stars d) super giants e) novae
b
The measurement of a star's brightness is called a) temperature c) parallax b) magnitude d) period e) pulsation
b
The red shifts exhibited by galaxies can be explained by. a) calculation errors c) Kepler's first law e) a collapsing universe b) an expanding universe d) expansion of the Milky Way
b
The two properties of a star that are plotted on an H-R diagram are a) size and distance b) brightness and temperature c) speed and distance d) size and temperature e) brightness and distance
b
Which force is most responsible for the formation of a star? a) magnetic c) nuclear b) gravity d) interstellar e) light pressure
b
Which one of the following stellar remnants has the greatest density? a) neutron star c) white dwarf b) black hole d) black dwarf
b
very massive stars terminate in a brilliant explosion called a a) red giant c) protostar b) supernova d) neutron star e) planetary nebula
b
The term big bang describes the [beginning/end) of the [solar system/galaxy/universe].
beginning
The theory that proposes that the universe originated as a single mass that subsequently exploded is referred to as the ----- theory.
big bang
An object even smaller and denser than a neutron star, with a surface gravity so immense that light cannot escape, is called a(n)
black hole
A(n) is an interstellar cloud that glows because of its proximity to a very hot (blue) star.
bright nebula
During the process referred to as hydrogen burning, hydrogen nuclei in the core of a star are fused together and become _nuclei. a) oxygen c) helium e) argon b) nitrogen d) carbon
c
On an H-R diagram, main-sequence blue stars are massive and a) cool c) hot b) white dwarfs d) novae e) supergiants
c
The Milky Way is a a) constellation b) red giant e) galactic cluster c) spiral galaxy d) dark nebula
c
The study of the properties and structure of the universe is called a) the Nebular theory c) cosmology b) the Big Bang theory d) Hubble's theory e) stellar variability
c
Which one of the following is NOT a type of nebula? a) reflection c) spiral b) emission d) dark
c
Which type of galaxy is composed mostly of young stars? a) nebulas c) irregular b) elliptical d) spiral e) nebular
c
The core of a red giant star is [expanding/contracting).
contracting
The observation that all galaxies, except those in the Local Group, appear to be moving away from the Milky Way is the
cosmological red shift
The study of the properties, structure, and evolution of the universe is called
cosmology
A very young, large, red object that is soon to become a star but is not yet hot enough for nuclear fusion is termed a a) black hole c) red giant e) white dwarf b) supernova d) protostar
d
One light-year is about a) 6 trillion kilometers b) 9.5 trillion miles e) 11 trillion kilometers c) 8 trillion kilometers d) 5.8 trillion miles
d
Stars with surface temperatures between 5000 and 6000 K appear a) red c) violet b) green d) yellow e) blue
d
The Sun is positioned about a) one-fourth b) one-third _ of the way from the center of the galaxy. c) one-half e) three-fourths d) two-thirds
d
The brightness of a star, if it were at a distance of 32.6 light-years, is its a) apparent magnitude c) apparent brightness e) mass-distance ratio b) parallax d) absolute magnitude
d
When a dense cloud of interstellar material is not close enough to a bright star to be illuminated, it is referred to as a(n)
dark nebula
------ is a type of very dense matter that forms when electrons are displaced inward from their regular orbits around an atom's nucleus
degenerate matter
Most of the stars in the Milky Way Galaxy are distributed in a [disk/sphere) with spiral arms.
disk
Some elliptical galaxies so small that they are known as
dwarf galaxies
A star with which one of the following magnitudes would appear the brightest? a) 15 c) 5 e) -5 b) 10 d) 1
e
According to the Big Bang theory, a cataclysmic explosion created the matter in the universe about years ago. a) 600 million c) 4.6 billion e) 14 billion b) 2 billion d) 12 billion
e
The apparent change in wavelength of radiation caused by the relative motions of the source and the observer is referred to as a) Hubble's law c) Newton's law of radiation e) the Doppler effect b) the acceleration factor d) relativity
e
The density of a white dwarf is such that a spoonful of its matter would weigh a) a kilogram c) 40 grams e) several tons b) 500 pounds d) a ton
e
the difference in the brightness of two stars having the same surface temperature is attributable to their relative e) sizes a) densities b) colors c) compositions d) ages
e
A type of galaxy that has an ellipsoidal shape that ranges to nearly spherical and lacks spiral arms is called a(n)
elliptical galaxy
A(n) is a gaseous interstellar mass that absorbs ultraviolet light from an embedded or nearby hot star and reradiates, or emits, this energy as visible light.
emission nebula
t or f A hot, massive blue star will age more slowly than a small (red) main-sequence star.
f - rapidly
t or f Absolute magnitude is the brightness of a star when viewed from Earth.
f apparent
t or f Stars that orbit one another are called neutron stars.
f binary
t or f Dark nebulae glow because they are close to very hot stars
f bright
t or f A first-magnitude star is about 100 times dimmer than a sixth-magnitude star.
f brighter
t of f Galaxies are receding from us at a speed that is proportional to their size.
f distance
t or f The light-year is a unit used to measure the age of a star.
f distance
t or f Spiral galaxies are the most abundant type of galaxies.
f elliptical
t or f Large Doppler shifts indicate low velocities.
f high
t or f The Milky Way is about 100,000 kilometers wide.
f light years
A system of galaxies containing from several to thousands of member galaxies is called a(n)_
galactic clusters
states that galaxies are receding from us at a speed that is proportional to their distance.
hobbles law
The combining of four hydrogen nuclei into a single helium nuclei is called
hydrogen fusion
A reflection nebula is thought to be composed of a rather dense cloud of large particles called
interstellar dust
A(n) -------- is a type of galaxy that lacks symmetry.
irregular galaxy
Stellar parallax [is/is not] detectable with the unaided eye.
is not
A(n) _ is a unit used to express stellar distance equal to about 9.5 trillion kilometers (5.8 trillion miles).
light year
Our own group of galaxies, called the , contains at least 28 galaxies.
local group
On an H-R diagram, the "ordinary" stars that are located along a band that extends from the upper-left corner to the lower-right comer are called
main-sequence stars
If the sizes of the orbits of binary stars can be measured, a determination of their individual [masses/temperatures] can be made.
masses
On an H-R diagram, among main-sequence stars, hot stars are (more/less] massive than cooler stars.
more
An interstellar cloud consisting of dust and gases is referred to as a(n)
nebula
Concentrations of interstellar dust and gases are called [nebulae/novas).
nebulae
A star consisting of matter formed from the combination of electrons with protons that is smaller and more massive than a white dwarf is called a(n)
neutron star
An expanding spherical cloud of gas, called a(n) , forms when a medium-mass star collapses from a red giant to a white dwarf star.
planetary nebula
A [white dwarf/protostar) is the first stage in the evolution of a star.
protostar
A collapsing cloud of gases and dust not yet hot enough to engage in nuclear fusion but destined to become a star is referred to as a(n)
protostar
Discovered in the early 1970s, a(n) is a neutron star that radiates short bursts of radio energy.
pulsar
Neutron stars rotate very [slowly/quickly].
quickly
Stars with surface temperatures less than 3000 K appear [blue/yellow/red).
red
A(n) is a very large, cool, reddish-colored star of high luminosity.
red giant
An interstellar cloud of gases and dust that merely reflects the light of nearby stars is called a(n)
reflection nebula
The Milky Way Galaxy is thought to be a(n) [spiral/elliptical] galaxy.
spiral
the Milky Way is a type of galaxy called a(n)
spiral galaxy
A(n) is an exceptionally large star, such as Betelgeuse, with a radius about 800 times that of the Sun and high luminosity.
supergiant
Neutron stars are believed to be produced by [nuclear fission/supernovae/degenerate matter].
supernova
Stars exceeding three solar masses have relatively short life spans and terminate in a brilliant explosion called a(n)
supernova
The atoms that compose our Sun, as well as the rest of the solar system, formed during a (supernova/galactic collision] event trillions of kilometers away.
supernova
t or f A rapidly rotating neutron star that radiates short pulses of radio energy is called a pulsar.
t
t or f A stable main-sequence star is balanced between the force of gravity and internal gas pressure.
t
t or f A star's color is primarily a manifestation of its temperature.
t
t or f All stars eventually exhaust their nuclear fuel and collapse in response to gravity.
t
t or f If there is enough matter in the universe, the outward expansion of the galaxies could eventually stop.
t
t or f Low-mass stars evolve to become white dwarfs.
t
t or f On an H-R diagram, the Sun is a main-sequence star.
t
t or f On an H-R diagram, the hottest main-sequence stars are intrinsically the brightest.
t
t or f Stars with equal surface temperatures radiate the same amount of energy per unit area.
t
t or f The larger the magnitude number, the dimmer the star.
t
t or f giant stars are cooler than white dwarfs.
t
t or f star with a surface temperature less than 3000 K will generally appear red.
t
Stars that fluctuate regularly in brightness by expanding and contracting in size are called
variable stars
A(n) is a small, dense star that was once a low-mass or medium-mass star whose internal heat energy was able to keep these gaseous bodies from collapsing under their own weight.
white dwarf
As matter is pulled into a black hole, it emits a steady stream of [radio waves/X-rays).
x-rays