1. Extrasolar planets:
a) Have not yet been discovered, but astronomers are hoping to discover some in the next few decades.
b) Are orbiting the Sun outside the orbit of Pluto.
c) Are planets that have been found orbiting other stars besides the Sun.
d) Can be seen without a telescope from Earth, at a dark site.
e) Are found by studying the light from distant galaxies.

2. Which of the following types of stars has the longest main sequence lifetime?
a) O.
b) M.
c) K.
d) G.
e) B.

3. A white dwarf is:
a) A ball of neutrons.
b) A black hole.
c) The remaining core of a star like the Sun, after it has shed its outer layers.
d) The left-over core of a massive star, after it has exploded in a supernovae.
e) A star with hydrogen fusion in its core.

4. Approximately how long does it take before the hydrogen runs out in the core of a type G main sequence star?
a) 3 million years.
b) 10 million years.
c) 10 billion years.
d) a trillion years.
e) a hundred trillion years.

5. Which of the following types of main sequence stars has the biggest mass?
a) M.
b) K.
c) G.
d) B.
e) O.

6. Which of the following types of stars produce the most UV light, compared to the amount of light they emit in the optical?
a. G.
b. M.
c. O.
d. K.
e. F.

7. Most of the extrasolar planets discovered so far have been found by:
a) direct observation of the planet.
b) observation of the spectrum of the planet.
c) observation of a `wobble' in the position of the planet's star with time.
d) periodic redshifting and blueshifting of the light from the planet's star.
e) observation of a periodic dimming of the light from the planet's star due to eclipses by the planet.

8. Which of the following statements is true about the lifetimes of main sequence stars?
a) Colder main sequence stars live longer than hotter main sequence stars.
b) Main sequence A stars live longer than main sequence K stars.
c) Type O main sequence stars live longer than type M main sequence stars.
d) The greater the mass of a star, the longer its main sequence lifetime.
e) All main sequence A stars ever formed are still main sequence A stars.

9. Main sequence M stars are:
a. the hottest known stars.
b. brown dwarfs.
c. very short-lived stars.
d. inert balls of neutrons.
e. fusing hydrogen to helium in their cores.

10. Extrasolar planets:
a) is the generic name for the four largest planets: Jupiter, Saturn, Uranus, or Neptune.
b) are white dwarfs.
c) Can be found by observing their gravitational effect on their star.
d) May exist, but have never been found.
e) Probably do not exist.

11. The group of galaxies we live in is called:
a) The Virgo Cluster.
b) The Local Group.
c) The Cosmic Group.
d) The Drake Group of Galaxies.
e) The Astronomical Unit.

12. The Milky Way:
a) Is rotating on its axis.
b) Is moving towards the Andromeda Galaxy.
c) Is part of the Local Group of Galaxies.
d) Is about 100 thousand light years in diameter.
e) All of the above.

13. The Andromeda Galaxy:
a) is a billion times larger than the Milky Way.
b) is a billion times smaller than the Milky Way.
c) is about the same size as the Milky Way.
d) is a small elliptical galaxy, about 100 times smaller than the Milky Way.
e) is a giant elliptical galaxy, about 100 times the diameter of the Milky Way.

14. The Andromeda Galaxy and the Milky Way Galaxy:
a) are eventually going to merge.
b) are both tiny dwarf irregular galaxies.
c) are both in the Virgo Cluster.
d) are both elliptical galaxies.
e) are moving away from each other.

15. Looking at a periodic table, determine what is produced when an alpha capture process happens in a stellar core made up of mainly ²⁴Mg? (note: a link to a periodic table is available from the course web site, under `extra information').
a) ²⁶Mg
b) ²⁶Si
c) ²⁸Al
d) ²⁸Si
e) ²⁸S

16. Which of the following chemical elements is more abundant in the Universe?
a) Uranium.
b) Silicon.
c) Iron.
d) Magnesium.
e) Carbon.

17. White dwarfs are made up of mainly:
a) neutrons.
b) hydrogen.
c) helium, carbon, and/or oxygen.
d) silicon, magnesium, and nickel.
e) iron.

18. The iron in our blood was probably originally produced:
a) in the Big Bang.
b) in a main sequence one solar mass star.
c) in a one solar mass star, after it become a variable star.
d) during a supernova explosion.
e) in a massive star, just before it explodes as a supernova.

19. Only one of the following has nuclear reactions in its core. Which one?
a) an interstellar cloud.
b) Jupiter.
c) an isolated white dwarf star.
d) a main sequence star.
e) an isolated neutron star.

20. An alpha particle is:
a) an ionized hydrogen atom.
b) a ²H nucleus.
c) a ⁴He nucleus.
d) a carbon-12 nucleus.
e) an ⁵⁶Fe nucleus.

21. A planetary nebula is:
a) a rapidly expanding gas cloud, caused by the explosion of a massive star.
b) a cloud of gas ejected from a low mass star like the Sun in the process of dying.
c) a collection of asteroids around a star.
d) a supernova.
e) a gas cloud forming into a solar system.

22. The uranium on Earth was probably produced:
a) in the core of the Sun.
b) in the core of a red giant star.
c) in a white dwarf star.
d) in a planetary nebula.
e) in a supernova explosion.

23. An alpha capture reaction is:
a) When an ion combines with an electron.
b) When an electron and a proton combine to form a neutron and a neutrino.
c) When a helium nucleus fuses with a heavier nucleus (such as an oxygen nucleus).
d) During a supernova, when a neutron fuses with an atom.
e) When four hydrogen nuclei fuse to form a helium nucleus.

24. A ⁴He nucleus is also called:
a) an alpha particle.
b) a beta particle.
c) deuterium.
d) deuteron.
e) a positron.

25. The types of stars, from hottest to coldest, are:
a) OBFGKAM.
b) ABFGKMO.
c) OBAFGKM.
d) MKGFABO.
e) OMKGFBA.

26. What is the main sequence lifetime of a 1 solar mass star?
a) a million years.
b) a billion years.
c) 10 billion years.
d) 100 billion years.
e) a trillion years.

27. Which planet in our solar system is tidally locked to the Sun?
a. Mercury.
b. Venus.
c. Earth.
d. Pluto.
e. None.

28. Some of the newly-discovered extrasolar planets are likely tidally locked to their parent star. This means:
a. They spin once on their axis for each orbit around the star.
b. The star always keeps the same face to the planet.
c. The planet does not spin on its axis.
d. The star does not spin on its axis.
e. The planet does not orbit the star, but instead remains in the same location.

29. The Earth is 81 times more massive than the Moon. How does the gravitational force on the Earth due to the Moon compare with the gravitational force on the Moon due to the Earth?
a) the gravitational force on the Earth due to the Moon is 81 times smaller.
b) the gravitational force on the Earth due to the Moon is 81² = 6561 times smaller.
c) the gravitational force on the Earth due to the Moon is square root of 81 = 9 times smaller.
d) the gravitational force on the Earth due to the Moon is 81 times larger.
e) the two forces are the same.

30. Light Bulb A has a yellowish glow, Light Bulb B has a reddish glow, and Light Bulb C has a blueish white glow. Therefore, in order of temperature, from coldest to hottest, the filaments in the bulbs are:
a) A, B, C.
b) C, A, B.
c) A, C, B.
d) B, A, C.
e) C, B, A.

31. If the velocity-vs.-time plot of a star perturbed by a planet orbiting around it is a perfect sinusoidal shape, then the orbit is:
a) an elongated ellipse, and the planet moves at constant speed along its orbit.
b) an elongated ellipse, and the planet moves at varying speed along its orbit.
c) a perfect circle.
d) in the plane of the sky; no motion radially with respect to us.
e) we are not yet able to detect such perturbations of stars by planets.

32. The first stars formed in the Universe were made up of almost all:
a) carbon, oxygen, and nitrogen.
b) hydrogen and helium.
c) neutrons.
d) iron, oxygen, and nitrogen.
e) iron, oxygen, and magnesium.

33. If a planet orbits a star in an elliptical orbit, its speed is:
a) the same throughout its orbit.
b) fastest when the planet is closest to the star.
c) fastest when the planet is furthest from the star.
d) planets always orbit stars in circular orbits.
e) outside our solar system, no other planets have been found yet, so we don't know what their orbits are like.

34. Star A has a surface temperature of 5000K, while Star B has a surface temperature of 10,000K. Therefore the wavelength of the peak of the spectrum of Star A is:
a) Half that of the wavelength of the peak of the spectrum of Star B.
b) Twice that of the wavelength of the peak of the spectrum of Star B.
c) The same as the wavelength of the peak of the spectrum of Star B.
d) Four times that of the wavelength of the peak of the spectrum of Star B.
e) One quarter that of the wavelength of the peak of the spectrum of Star B.

35. If the hydrogen lines in the spectrum of a star are observed at wavelengths shorter than the wavelengths measured in the laboratory, this means:
a) the star is very hot.
b) the star is very cold.
c) the star is moving towards us.
d) the star is moving away from us.
e) the star is moving in the plane of the sky, with no radial motion relative to us.

36. The Earth is 81 times more massive than the Moon. How does the acceleration of the Earth due to the Moon compare with the acceleration of the Moon due to the Earth?
a) the acceleration of the Earth due to the Moon is 81 times smaller.
b) the acceleration of the Earth due to the Moon is 81² = 6561 times smaller.
c) the acceleration of the Earth due to the Moon is square root of 81 = 9 times smaller.
d) the acceleration of the Earth due to the Moon is 81 times larger.
e) the two accelerations are the same.

37. Newton's First Law of Motion (also known as the Law of Inertia) can be paraphrased as:
a) F = MA
b) F₁ = F₂
c) objects in motion with no forces acting on them tend to slow down and stop.
d) objects in motion keep moving with constant velocity unless acted upon by a force.
e) objects in motion keep moving with constant acceleration unless acted upon by a force.

38. Newton's Second Law of Motion can be paraphrased as:
a) when a force is applied to an object, the velocity of the object is proportional to its mass.
b) when a force is applied to an object, the acceleration of the object is proportional to its mass.
c) when a force is applied to an object, the velocity of the object is inversely proportional to its mass.
d) when a force is applied to an object, the acceleration of the object is inversely proportional to its mass.
e) when a force is applied to an object, the acceleration of the object is proportional to its mass squared.

39. Imagine you have two balls, Ball A and Ball B. Ball A has ten times the mass of Ball B. If they are hit with the same force:
a) they accelerate at the same rate.
b) Ball A accelerates ten times as fast as Ball B.
c) Ball A accelerates 100 times as fast as Ball B.
d) Ball A accelerates 1/10th as fast as Ball B.
e) Ball A accelerates 1/100th as fast as Ball B.

40. The difference between a brown dwarf and a white dwarf is:
a) a white dwarf currently has hydrogen fusion in its core; a brown dwarf doesn't.
b) a brown dwarf currently has hydrogen fusion in its core; a white dwarf doesn't.
c) neither currently has hydrogen fusion; a brown dwarf did in the past, while a white dwarf did not.
d) neither currently has hydrogen fusion; a white dwarf did in the past, while a brown dwarf did not.
e) Brown dwarf and white dwarf are two names for the same thing.

41. What is ONE reason that most astronomers believe that lifeforms are less likely to exist on planets orbiting main sequence O and B stars?
a. These stars don't produce enough light.
b. These stars produce a lot of infrared radiation, which is dangerous to lifeforms.
c. These stars have short lifetimes, so there might not have been time for life to have developed.
d. These stars do not have nuclear reactions going on inside them.
e. These stars are very dense balls of neutrons.

42. Our Sun is a yellow star, Betelgeuse has a reddest tint, and Rigel appears blue-white. This means that the surface temperature of the Sun is:
a. hotter than Rigel and colder than Betelgeuse.
b. colder than Rigel and hotter than Betelgeuse.
c. hotter than both Rigel and Betelgeuse.
d. colder than both Rigel and Betelgeuse.
e. the same temperature as Rigel and Betelgeuse.

43. According to Newton's First Law of Motion:
a) If no force acts upon a moving object, it will slow down and stop.
b) If no force acts upon a moving object, it will move in a circle.
c) If no force acts upon a moving object, it will continue moving in a straight line at a constant speed.
d) For every acceleration, there is an equal and opposite acceleration.
e) The acceleration of an object is proportional to its mass.

44. Our Sun is what type of star?
a) M.
b) K.
c) G.
d) B.
e) O.

45. The type of stars with the shortest main sequence lifetimes are:
a) M stars.
b) K stars.
c) G stars.
d) B stars.
e) O stars.

46. Planetary transits, when extrasolar planets pass directly in front of their parent stars, have been observed by:
a) observing a `wobble' in the position of the star in the sky with time.
b) observing a slight `dimming' of the brightness of the star with time.
c) observing the spectral lines of the planet.
d) directly imaging the planet itself.
e) no such planetary transits have yet been observed.

47. Looking at the periodic table on the wall, determine what is produced when an alpha capture process happens to a ²⁸Si atom?
a) ³⁰Si
b) ²⁹P
c) ³²S
d) ³⁶S
e) ⁴⁰Ar

48. The visible spectrum of the Sun shows:
a) a continuous bright spectrum, crossed by many dark absorption lines.
b) a uniform continuous spectrum, with the same level of brightness at all wavelengths.
c) only a few bright emission lines.
d) only yellow light.
e) a perfect blackbody spectrum.

49. An atom will emit light at a particular wavelength when an electron in the atom:
a) escapes from the atom
b) drops to an inner orbit
c) jumps to a higher orbit
d) collides with an atom
e) becomes a proton

50. What produces a spectrum with ONLY certain color (wavelength) bright lines?
a) a low density gas.
b) a high density gas.
c) a low density gas in front of a hot dense gas.
d) a low density gas in front of a hot solid.
e) a hot solid.

51. An emission-line spectrum:
a) is produced by a hot solid object.
b) is sometimes called a dark line spectrum, since it looks like a continuous spectrum with dark lines across it.
c) is produced by a low density gas in front of a source of continuous light.
d) is a spectrum where light is seen at all wavelengths, except at certain specific wavelengths.
e) is a spectrum in which light is only seen at certain specific wavelengths.

52. Which of the following types of main sequence stars take the longest to use up the hydrogen in their cores, by turning it into helium?
a. G.
b. M.
c. O.
d. K.
e. F.

53. The plot to the right shows the velocity-vs.-time plot for a star perturbed by the motion of a planet. The shape of this curve tells astronomers that the extrasolar planet:
a) orbits the star in a perfect circle.
b) orbits the star in the plane of the sky.
c) orbits the star in an ellipse.
d) has hydrogen fusion in its core.
e) there is no evidence that extrasolar planets exist.

54. To detect an extrasolar planet DIRECTLY (i.e., see its disk or its spectrum), what wavelengths of light are best?
a) infrared.
b) visible.
c) ultraviolet.
d) radio waves.
e) X-rays.

55. Our Sun is eventually going to become:
a) A supernova, then a neutron star.
b) A planetary nebula and a white dwarf.
c) A supernova, then a white dwarf.
d) A planetary nebula, then a neutron star.
e) A supernova, then a black hole.

Answers: 1c, 2b, 3c, 4c, 5e, 6c, 7d, 8a, 9e, 10c, 11b, 12e, 13c, 14a, 15d, 16e, 17c, 18e, 19d, 20c, 21b, 22e, 23c, 24a, 25c, 26c, 27e, 28a, 29e, 30d, 31c, 32b, 33b, 34b, 35c, 36a, 37d, 38d, 39d, 40d, 41c, 42b, 43c, 44c, 45e, 46b, 47c, 48a, 49b, 50a, 51e, 52a, 53c, 54a, 55b.