1. Which of the following describes a solar eclipse?
a. the earth is between the sun and the moon, and the earth is in the
moon's shadow
b. the earth is between the sun and the moon, and the moon is in the
earth's shadow
c. the moon is between the earth and the sun, and the moon is in the
earth's shadow
d. the moon is between the earth and the sun, and the earth is in the
moon's shadow
2. What is a light year?
a. a unit of time equal to 6 trillion seconds
b. the average distance between the Earth and the Sun
c. the distance light travels in a year
d. the time the Earth takes to orbit the Sun
3. What is a parsec?
a. a unit of time equal to about 3.26 million seconds
b. a unit of angle equal to 1/3600 of a degree
c. the distance light travels in a year
d. the distance at which the parallax angle is 1 arcsecond
4. That famous observing team of Drs. Harden, Petrie, and Rozyczka measures
the parallaxes of the stars Sirius and Altair. They find that Sirius has
a parallax angle of 0.30 arcsecond, and Altair has a parallax angle of 0.15
arcsecond. What do they conclude?
a. Sirius is twice as far away as Altair
b. Altair is twice as far away as Sirius
c. Sirius is twice as large as Altair
d. Altair is twice as large as Sirius
5. Drs. Harden, Petrie, and Rozyczka have discovered a Cepheid in a distant
galaxy, and want to determine exactly how distant that galaxy is. They
have measured the Cepheid's period and brightness. Can they determine its
distance?
a. yes, by using the period-luminosity relation to find the luminosity,
and with the luminosity and brightness they can find the distance
b. yes, by measuring its trigonometric parallax
c. yes, by measuring the Doppler shift of its spectrum
d. no, they would need to know its radius to do that
6. The wavelength of blue light is about half that of red light. The
frequency of blue light is ______________ that of red light, and the
energy of a blue light photon is ______________ that of a red light
photon.
a. half, half
b. two times, four times
c. two times, two times
d. four times, four times
7. The Keck telescope has four times the diameter of the Hubble Space
Telescope. Ignoring the effects of Earth's atmosphere, the Keck telescope
has _____________ angular resolution and _____________ the
light-collecting power of the Hubble Space Telescope.
a. one fourth as good; one sixteenth
b. one half as good; four times
c. four times better; sixteen times
d. four times better; four times
8. Mars orbits the sun at a distance of approximately 1.5 AU. What is its
orbital period in years?
a. the cube root of 1.5, which is about 1.14
b. the square root of 1.5, which is about 1.22
c. the cube root of 1.5 squared, which is about 1.31
d. the square root of 1.5 cubed, which is about 1.84
9. Proxima Centauri, the nearest star to the sun, is a Main Sequence star
that is cooler than the sun. Where on the H-R diagram would it be found?
a. above and to the right of the sun
b. above and to the left of the sun
c. below and to the right of the sun
d. below and to the left of the sun
For questions 10, 11, and 12: Alpha Centauri is a binary, consisting of
two Main Sequence stars, Alpha Centauri A and Alpha Centauri B. Alpha
Centauri A is a one-solar-mass star, and Alpha Centauri B is a
one-half-solar-mass star. They are separated by about 10 AU, the
distance between the sun and Saturn.
10. Alpha Centauri A is yellow. What color is Alpha Centauri B?
a. orange
b. yellow
c. blue
d. a one-half-solar-mass star is too cool to fuse hydrogen, so it doesn't
emit any visible light
11. Alpha Centauri A takes 30 years to orbit the binary's center of mass.
How long does Alpha Centauri B take to orbit the center of mass?
a. 15 years
b. 30 years
c. 60 years
d. 900 years
12. Which star will leave the Main Sequence first?
a. Alpha Centauri A, because it is more massive
b. Alpha Centauri B, because it is less massive
c. they will both leave at the same time, because they were born together
d. there is no way to tell, because the stars are touching each other and
exchanging mass
13. When does a protostar become a star?
a. when it begins to fuse hydrogen in its core
b. when its mass becomes greater than half a solar mass
c. when the peak of its spectrum moves into visible light
d. when the cloud of gas and dust around it is cleared away
14. Which phase in a low-mass star's evolution lasts longest?
a. protostar
b. Main Sequence
c. red giant
d. horizontal branch
15. What is the difference between a red giant and an asymptotic giant?
a. an asymptotic giant's interior is like a red giant's, but its surface
is hotter, so it's not red
b. high-mass stars become red giants; low-mass stars become asymptotic
giants
c. an asymptotic giant is a star that is traveling up the giant branch
and will eventually become a red giant
d. a red giant has a degenerate helium core; an asymptotic giant has a
degenerate carbon core
16. The Pleiades and the Hyades are two star clusters in the constellation
of Taurus. The Pleiades has many bright blue stars but no bright red
stars, and the Hyades has many bright red stars and few bright blue stars.
What can we conclude?
a. the Pleiades is older than the Hyades
b. the Hyades is older than the Pleiades
c. the Pleiades is closer than the Hyades
d. the Hyades is closer than the Pleiades
17. Drs. Harden, Petrie, and Rozyczka discover a binary system consisting
of a white dwarf of about 1.4 solar masses and a red giant of about 2
solar masses. They report that the red giant seems to be losing mass,
which is going onto the white dwarf. What will happen to this system
when the white dwarf exceeds the Chandrasekhar limit?
a. the white dwarf will collapse into a black hole
b. a Type I supernova
c. a Type II supernova
d. mass will start flowing back onto the red giant
18. Which of the following fusion reactions cannot produce
energy to keep a star from collapsing in on itself?
a. hydrogen into helium
b. helium into carbon
c. silicon into iron
d. iron into tellurium
19. How big is a neutron star?
a. about the size of San Francisco (about 12 kilometers across)
b. about the size of the Earth
c. about the size of the Sun
d. about the size of the orbit of Mars
20. Why are black holes black?
a. because they are white dwarfs that have lost all their remnant heat
b. because they are so hot they only emit light in the ultraviolet
c. because their escape velocity is greater than the speed of light, so
any light they emit can't escape
d. because they are moving away from us so quickly, their light is
redshifted out of the visible range