REVIEW FOR TEST 2

The Giant Planets

1. The gas giants are composed mainly of what two elements?

1. Hydrogen & oxygen
2. Hydrogen & nitrogen
3. Hydrogen & helium
4. Helium & oxygen

2. Which gas giants have rings?

1. Saturn & Neptune
2. Saturn & Jupiter
3. Saturn & Uranus
4. All gas giants have rings

3. Which of the following is true of the Roche Limit?

1. Moons are located inside it, rings are located outside
2. Rings are located inside it, moons are located outside
3. Only applies to the gas giant planets.
4. Defines the distance at which asteroids transition from stony and metal-rich to black and carbon-rich

4. T/F: The majority of the solar system’s moons orbit the giant planets.

5. Which of these is the largest:

1. Earth’s moon
2. Pluto
3. Mercury
4. Ganymede (Jupiter’s largest moon)

6. True/False: Saturn has no moons.

7. Because Pluto’s orbit is _________ elliptical than the other orbits in our solar system, it sometimes crosses Neptune’s orbit.

1. More
2. Less

Interplanetary Bodies

8. The ancient preplanetary bodies which accreted to form planets are called

1. interstellar dust
2. planetesimals
3. sublimates
4. meteors

9. Which of the following is not a part of a comet?

1. nucleus
2. coma
3. tail
4. stream

10. True/False: Comets orbiting the sun are not bound by Kepler’s laws.

11. The asteroid belt is located between which two planets?

1. Venus and Earth
2. Earth and Mars
3. Mars and Jupiter
4. Jupiter and Saturn

12. A group of comets concentrated just beyond Pluto (at a distance of 30-100 AU) and lying roughly in the plain of the solar system is called the

1. Kuiper belt
2. Oort cloud
3. Trojan asteroids
4. planetesimals

13. Contrary to popular belief, a comet actually has how many tails?

1. 0
2. 1
3. 2
4. 3

14. Which of the following statements is TRUE?

a. All asteroids, by definition, lie in the asteroid belt between Mars and Jupiter.

b. Asteroids are capable of having an orbiting moon.

c. According to estimates, asteroids appear to consist of solid rock.

d. Asteroids have been known to do widespread damage to early civilizations.

16. Meteor showers occur when

1. asteroids break up in Earth's atmosphere.
2. the heads of comets collide with Earth's atmosphere.
3. when Earth's motion through the Galaxy takes it through a swarm of stars.
4. Earth passes through debris from a disintegrating comet.

17. Astronomers are interested in comets primarily because

a. they tell us about conditions in the solar nebula from which planets formed.

b. a collision with one would pose a major threat to continued life on the Earth.

c. they tell us about conditions in interstellar space.

d. none of the above. Astronomers are NOT interested in comets.

18. Suspected to be members or ex-members of the Kuiper Belt:

a. Pluto.

b. short-period comets.

c. icy moons of the outer solar system such as Triton and Charon.

d. all of the above.

19. An impact the size of the one that wiped out the dinosaurs probably occurs once every

1. 10 thousand years
2. 1 million years
3. 100 million years
4. 1 billion years

How Planetary Systems Form

20. Most of the mass in the solar system is in the __________. Most of the angular momentum in the solar system is in the __________.

1. sun, sun
2. sun, planets
3. planets, sun
4. planets, planets

21. The solar nebula hypothesis makes use of the temperatures at which different minerals condense to form solids to explain

a. how planetesimals stuck together to form the planets of the solar system.

b. why it is that water is such a rare substance in the solar system, found only on Earth.

c. why the planets are composed of different chemicals in different amounts.

d. how the cloud from which the solar system condensed ended up as a flattened disk.

22. The gradual accumulation of material to make large objects is called

1. aggregation
2. accretion
3. combination
4. sublimation

23. During the solar system formation, where did iron & ices of volatiles condense, respectively?

1. iron & volatiles both in the inner zone
2. iron & volatiles both in the outer zone
3. iron in the inner zone, volatiles in the outer zone
4. iron in the outer zone, volatiles in the inner zone

24. So far, the most successful technique for detecting extrasolar planets has been

1. measuring the doppler shift of a star
2. direct imaging of the planet with a telescope
3. no extrasolar planets have been detected

25. As the solar nebula collapsed,

a. the amount of angular momentum remained the same.

b. it gradually flattened to a disk-shaped cloud.

c. the bulk of the gas ended up in the Sun.

d. all of the above.

26. The condensation sequence agrees with the observation of ammonia and methane ices found

a. in comets and in the atmospheres and on the satellites of the giant planets.

b. in the Earth's polar regions.

c. on asteroids.

d. only within the inner portions of the solar system.

Detecting Radiation from Space

28. The distance between two successive peaks or troughs of a wave is called

1. frequency
2. wavelength
3. period
4. amplitude

29. Which is the correct order according to increasing wavelength?

1. microwave, gamma ray, X-ray, infrared, visible, ultraviolet, radio
2. visible, gamma ray, ultraviolet, infrared, X-ray, microwave, radio
3. Gamma ray, X-ray, ultraviolet, visible, infrared, microwave, radio
4. radio, microwave, infrared, visible, ultraviolet, X-ray, gamma ray

30. An individual piece (quantum) of light is called a

1. photon
2. proton
3. neutron
4. neutrino

31. An atom in the ground state can have

1. neither emission nor absorption lines
2. both emission and absorption lines
3. only emission lines
4. only absorption lines

32. An absorption line may appear as a

1. Red line against a black spectrum
2. Black line against a colored spectrum
3. Both A and B

33. An emission line which has been shifted to a longer wavelength is said to be

1. Retrograde
2. Red shifted
3. Blue shifted
4. Emission lines cannot be shifted

34. A well known example of an interferometer is

1. Russian space station Mir
2. The Hubble telescope
3. the Arecibo radio telescope as seen on the X-files and in James Bond: Goldeneye
4. the Very Large Array (VLA) as seen in the movie Contact

35. Using Wien’s law (l*T = 3*10⁶ nm*K), a star at a temperature of 1*10⁴ K would radiate at a wavelength of

1. 3*10² nm
2. 3*10⁴ nm
3. 3*10⁶ nm
4. 3*10¹⁰ nm

36. From Wien’s law, which wavelength corresponds to the highest temperature?

1. 10 m/s
2. 100 nm
3. 250 m/s
4. 500 nm

37. Humans radiate in which region of the electromagnetic spectrum?

1. Ultraviolet
2. Visible
3. Infrared
4. Humans don’t radiate, only stars can radiate

38. According to the Stefan-Boltzmann law (L = 4pR²sT⁴), which of the following will increase the luminosity of a star?

1. decreasing distance to the star
2. decreasing mass
3. increasing radius
4. decreasing temperature

39. What characteristic or behavior does an excited atom possess or exhibit?

a. It may emit one or more photons.

b. All of its electrons are in the ground state.

c. It is ionized.

d. It exhibits the Doppler effect.

40. Which of the following statements regarding radiation is TRUE?

a. All wavelengths travel at the speed of light.

b. Any wavelength can get through the "radio window" if it slows down.

c. Radio wavelengths are shorter than X-ray wavelengths.

d. In general, ultraviolet radiation is less harmful than microwave radiation.

41. In general, the primary function of a telescope is

a. to measure the wavelengths of the incoming types of radiation.

b. separate out one type of radiation from another.

c. act as a "light bucket" to catch photons.

d. measure the amount of radiation produced inside of an object in space.

Our Sun: the Nearest Star

42. Cool gas between an observer and a continuous light source will cause

1. an absorption line spectrum
2. an emission line spectrum
3. a continuous spectrum
4. the continuous light source to appear “pulsed”

43. The two most common elements in the solar system are

1. hydrogen and helium
2. hydrogen and oxygen
3. helium and nitrogen
4. helium and oxygen

44. What is the outermost layer of the sun?

1. core
2. corona
3. photosphere
4. chromosphere

45. What is the hottest layer of the sun?

1. core
2. corona
3. photosphere
4. chromosphere

46. About how long does it take light from the sun to reach the earth?

1. instantaneous
2. 8 minutes
3. 2 hours
4. 1 light year

47. Sunspots appear dark because they are

1. slightly cooler than the surrounding photosphere
2. slightly hotter than the surrounding photosphere
3. a different composition than the rest of the photosphere
4. they do not appear any darker

48. Using the equation for parallax d = 1 / p, if the parallax of a star is p = 2 arcsec, the distance to the star is

1. 2 AU
2. 2 parsecs
3. ½ AU
4. ½ parsecs

Properties of Stars

49. What is the correct spectral class sequence in order from highest to lowest temperature?

1. O B A F G K M
2. O B F M A G K
3. A B F G K K O
4. M K G F A B O

50. Which of the following cannot be determined based solely on the axes of the H-R diagram?

1. Luminosity (L/L_sun)
2. Effective temperature (K)
3. Apparent Magnitude
4. Spectral Class

51. Along the main sequence of the H-R diagram, stars follow a mass-radius relation. This means that

1. more massive stars are brighter
2. more massive stars are hotter
3. more massive stars are bigger
4. more massive stars are smaller

52. Which of the following types of stars can be found on the main sequence of the H-R diagram?

1. white dwarfs
2. red dwarfs
3. giants
4. supergiants

53. Dr. McGaugh stressed in class that “the main sequence is a sequence in mass.” This means that the most massive stars on the main sequence are located where?

1. at the bottom right
2. in the middle
3. at the top left
4. anywhere on the sequence

54. For main sequence stars, the general rule is: the higher the surface temperature, the

a. more numerous are the stars.

b. greater the masses of the stars.

c. less luminous are the stars.

d. more common are binary stars.

55. If two observations of the stars Sirius and Arcturus are made at 6 month intervals, Sirius reveals a greater parallax because Sirius is

a. closer to us than Arcturus.

b. hotter than Arcturus.

c. more massive than Arcturus.

d. more distant than Arcturus.

56. A star's luminosity is

a. dependent on the star's size and distance.

b. calculated by measuring the star's parallax angle.

c. dependent on the star's temperature and amount of surface area.

d. expressed as its apparent visual magnitude.

57. The brightest stars we observe in the sky

a. are typically the nearest stars to Sun.

b. are generally stars with low luminosities.

c. have mv's with large positive numbers (between +10 and +30).

d. are generally cooler red giant and hot young stars.

58. The typical distance between stars is

a. not well understood since distances to stars are difficult to determine.

b. one astronomical unit.

c. one parsec.

d. one light-year.

59. If a star is said to be in hydrostatic equilibrium, it is not contracting because

1. the ratio of H to He is equal
2. its temperature is too low
3. its internal pressure balances its gravity
4. it is too dense to contract further

ANSWER KEY

1. C

2. D

3. B

4. T

5. D

6. F

7. A

8. B

9. D

10. F

11. C

12. A

13. C

14. B

15. C

17. A

18. D

19. C

20. B

21. C

22. B

23. C

24. A

25. D

26. A

28. B

29. C

30. A

31. D

32. B

33. B

34. D

35. A

36. B

37. C

38. C

39. A

40. A

41. C

42. A

43. A

44. B

45. A

46. B

47. A

48. D

49. A

50. C

51. C

52. B

53. C

54. B

55. A

56. C

57. D

58. C

59. C