Roger Freedman • Robert Geller • William Kaufmann III
Universe
Tenth Edition
Clicker Questions
Chapter 17
The Nature of the Stars
Parallax measurements are best made using a telescope
in orbit. This is because
A.
a telescope in orbit is closer to the stars.
B.
larger telescopes can be placed in orbit and so the
resolution is significantly improved.
C.
the baseline is longer and so the parallax angle is larger.
D. chromatic aberration from the telescope lens is
eliminated.
E.
an observatory in space is unhampered by the Earth’s
atmosphere.
Q17.1
Parallax measurements are best made using a telescope
in orbit. This is because
A.
a telescope in orbit is closer to the stars.
B.
larger telescopes can be placed in orbit and so the
resolution is significantly improved.
C.
the baseline is longer and so the parallax angle is larger.
D. chromatic aberration from the telescope lens is
eliminated.
E.
an observatory in space is unhampered by the Earth’s
atmosphere.
A17.1
The Hipparcos satellite measures a stellar parallax angle
of 0.05 arcsec for a nearby star. What is the distance to
this star in parsecs?
A. 0.05 parsecs
B. 6.1 parsecs
C. 3.26 parsecs
D. 20 parsecs
E. 65.2 parsecs
Q17.2
The Hipparcos satellite measures a stellar parallax angle
of 0.05 arcsec for a nearby star. What is the distance to
this star in parsecs?
A. 0.05 parsecs
B. 6.1 parsecs
C. 3.26 parsecs
D. 20 parsecs
E. 65.2 parsecs
A17.2
The Hipparcos satellite measures a stellar parallax angle
of 0.05 arcsec for a nearby star. What is the distance to
this star in light-years?
A. 0.05 light-years
B. 6.1 light-years
C. 3.26 light-years
D. 20 light-years
E. 65.2 light-years
Q17.3
The Hipparcos satellite measures a stellar parallax angle
of 0.05 arcsec for a nearby star. What is the distance to
this star in light-years?
A. 0.05 light-years
B. 6.1 light-years
C. 3.26 light-years
D. 20 light-years
E. 65.2 light-years
A17.3
At the distance of the Earth from the Sun (1 AU) the
intensity of sunlight is 1370 watts/m2. What is the intensity
at the distance of Saturn from the Sun (10 AU)?
A. 13,700 watts/m2
B. 1370 watts/m2
C. 137 watts/m2
D. 13.7 watts/m2
E. 1.37 watts/m2
Q17.4
At the distance of the Earth from the Sun (1 AU) the
intensity of sunlight is 1370 watts/m2. What is the intensity
at the distance of Saturn from the Sun (10 AU)?
A. 13,700 watts/m2
B. 1370 watts/m2
C. 137 watts/m2
D. 13.7 watts/m2
E. 1.37 watts/m2
A17.4
How bright is a star with a magnitude of +4.0 compared
to a star with magnitude +5.0?
A. 1/2.5 = 0.4 times as bright
B. equally bright
C. 1.25 times brighter
D. 2.5 times brighter
E. 10 times brighter
Q17.5
How bright is a star with a magnitude of +4.0 compared
to a star with magnitude +5.0?
A. 1/2.5 = 0.4 times as bright
B. equally bright
C. 1.25 times brighter
D. 2.5 times brighter
E. 10 times brighter
A17.5
Two stars have the same luminosity. As seen from Earth,
star #1 appears four times brighter than star #2. If star
#1 is 20 pc away, star #2
A. is 160 pc away.
B. is 80 pc away.
C. is 40 pc away.
D. is 10 pc away.
E. is 5 pc away.
Q17.6
Two stars have the same luminosity. As seen from Earth,
star #1 appears four times brighter than star #2. If star
#1 is 20 pc away, star #2
A. is 160 pc away.
B. is 80 pc away.
C. is 40 pc away.
D. is 10 pc away.
E. is 5 pc away.
A17.6
The spectral classification of a star is closely related to
the star’s
A. apparent brightness.
B. absolute magnitude.
C. luminosity.
D. surface temperature.
E. distance.
Q17.7
The spectral classification of a star is closely related to
the star’s
A. apparent brightness.
B. absolute magnitude.
C. luminosity.
D. surface temperature.
E. distance.
A17.7
The spectral type of the Sun is G2 and the spectral type of
the star Antares is M1.5. These facts imply that Antares
A. has a lower luminosity than the Sun.
B. is hotter than the Sun.
C. has a higher luminosity than the Sun.
D. is cooler than the Sun.
E. has the same luminosity and temperature as the
Sun.
Q17.8
The spectral type of the Sun is G2 and the spectral type of
the star Antares is M1.5. These facts imply that Antares
A. has a lower luminosity than the Sun.
B. is hotter than the Sun.
C. has a higher luminosity than the Sun.
D. is cooler than the Sun.
E. has the same luminosity and temperature as the
Sun.
A17.8
The spectrum of a certain star reveals that the H and He I
absorption lines are equally strong. The surface
temperature of this star is approximately
A. 3000 K
B. 6000 K
C. 9000 K
D. 10,000 K
E. 20,000 K
Q17.9
The spectrum of a certain star reveals that the H and He I
absorption lines are equally strong. The surface
temperature of this star is approximately
A. 3000 K
B. 6000 K
C. 9000 K
D. 10,000 K
E. 20,000 K
A17.9
Where is the Sun located on this H-R diagram?
A. A
B. B
C. C
D. D
E. E
Q17.10
Where is the Sun located on this H-R diagram?
A. A
B. B
C. C
D. D
E. E
A17.10
Which stars on this H-R diagram are on the main
sequence?
A. Vega, Sirius, and Mira
B. Stars at letters A and B
and Barnard’s Star
C. Sirius A and Sirius B
D. Rigel and Deneb
E. Pollux and Barnard’s Star
Q17.11
Which stars on this H-R diagram are on the main
sequence?
A. Vega, Sirius, and Mira
B. Stars at letters A and B
and Barnard’s Star
C. Sirius A and Sirius B
D. Rigel and Deneb
E. Pollux and Barnard’s Star
A17.11
Mira and Barnard’s star have different luminosities, as
can be seen from the H-R diagram. This difference
comes about because Mira has a
A. larger diameter than Barnard’s
star.
B. smaller diameter than
Barnard’s star.
C. higher surface temperature than
Barnard’s star.
D. lower surface temperature than
Barnard’s star.
E. the same diameter and surface
temperature as Barnard’s star.
Q17.12
Mira and Barnard’s star have different luminosities, as
can be seen from the H-R diagram. This difference
comes about because Mira has a
A. larger diameter than Barnard’s
star.
B. smaller diameter than
Barnard’s star.
C. higher surface temperature than
Barnard’s star.
D. lower surface temperature than
Barnard’s star.
E. the same diameter and surface
temperature as Barnard’s star.
A17.12
Betelgeuse has a very high luminosity (40,000 times
brighter than our Sun), but its surface is cool (less than
4000 K). Which of the following explains this?
A.
Betelgeuse must have a much smaller surface area than
the Sun.
B.
Betelgeuse is at the lower end of the main sequence.
C.
Betelgeuse is at the upper end of the main sequence.
D. Betelgeuse must have a much larger surface area than
the Sun.
E.
Q17.13
Betelgeuse must have the same surface area as the Sun.
Betelgeuse has a very high luminosity (40,000 times
brighter than our Sun), but its surface is cool (less than
4000 K). Which of the following explains this?
A.
Betelgeuse must have a much smaller surface area than
the Sun.
B.
Betelgeuse is at the lower end of the main sequence.
C.
Betelgeuse is at the upper end of the main sequence.
D. Betelgeuse must have a much larger surface area than
the Sun.
E.
A17.13
Betelgeuse must have the same surface area as the Sun.
A star must be in a binary system to measure its mass.
This is because
A.
single stars are not luminous enough to be measured.
B.
the mass is calculated from the gravitational interaction
between the stars in the system.
C.
the distance to binary stars can be measured more easily
than to single stars.
D. stellar diameters can be calculated for all binary stars and
the mass can then be determined.
E.
Q17.14
binary systems are more common than single stars.
A star must be in a binary system to measure its mass.
This is because
A.
single stars are not luminous enough to be measured.
B.
the mass is calculated from the gravitational interaction
between the stars in the system.
C.
the distance to binary stars can be measured more easily
than to single stars.
D. stellar diameters can be calculated for all binary stars and
the mass can then be determined.
E.
A17.14
binary systems are more common than single stars.