The present age of the Sun is about

1. The present age of the Sun is about A. 7000 years. • 100,000 years. • 5 billion years. D. 10 billion years.

2. The present age of the Sun is about A. 7000 years. • 100,000 years. • 5 billion years. • 10 billion years. Explanation: Five billion years ago, there was no Sun!

3. One astronomical unit (AU) is defined to be the distance from the Sun to A. Earth. • Jupiter. • the Kuiper Belt. D. the next nearest star.

4. One astronomical unit (AU) is defined to be the distance from the Sun to A. Earth. • Jupiter. • the Kuiper Belt. • the next nearest star.

5. Compared to the size of Earth, the Jovian planets are A. larger. • smaller. • a mixture of smaller and larger. D. more dense.

6. Compared to the size of Earth, the Jovian planets are A. larger. • smaller. • a mixture of smaller and larger. • more dense.

7. As a nebula shrinks under the influence of gravity, its rate of spin A. slows. • increases. • remains unchanged. D. turns into a protosun.

8. As a nebula shrinks under the influence of gravity, its rate of spin A. slows. • increases. • remains unchanged. • turns into a protosun. Explanation: In accord with the conservation of angular momentum, as the radius of the nebula decreases, its spin rate increases (like a skater who pulls her arms inward in a spin).

9. The energy source for the Sun or other stars is A. radiant energy. • chemical energy. • thermonuclear fusion. D. radioactivity.

10. The energy source for the Sun or other stars is A. radiant energy. • chemical energy. • thermonuclear fusion. • radioactivity.

11. Compared with the age of the Sun, the age of the universe is A. about the same. • slightly longer. • almost double. D. more than double.

12. Compared with the age of the Sun, the age of the universe is A. about the same. • slightly longer. • almost double. • more than double. Explanation: The universe is nearly 14 billion years old, more than twice the 5-billion-year age of the Sun.

13. Energy radiated by the Sun has its origin in A. decreasing mass. • increasing mass. • radioactive decay. • thermochemical reactions.

14. Energy radiated by the Sun has its origin in A. decreasing mass. • increasing mass. • radioactive decay. • thermochemical reactions. Explanation: A decrease in mass bathes the solar system with radiant energy. Solar mass is converted to energy via the celebrated equation, E = mc2.

15. The phase of matter composing the Sun is A. a tenuous solid. • a low-density liquid. • gaseous. D. plasma.

16. The phase of matter composing the Sun is A. a tenuous solid. • a low-density liquid. • gaseous. • plasma.

17. Rotation of the Sun is A. greater at the equator than in regions closer to the poles. • less at the equator than in regions closer to the poles. • in opposite directions on either side of its equator. D. a constant in the solar system.

18. Rotation of the Sun is A. greater at the equator than in regions closer to the poles. • less at the equator than in regions closer to the poles. • in opposite directions on either side of its equator. • a constant in the solar system.

19. The solar wind A. creates the tails of comets. • powers the aurora borealis on Earth. • is composed of high-speed electrons and protons. D. is all of the above.

20. The solar wind A. creates the tails of comets. • powers the aurora borealis on Earth. • is composed of high-speed electrons and protons. • is all of the above.

21. At eleven-year cycles, the Sun undergoes changes in A. rotational direction. • magnetic field reversal. • layer composition. D. all of the above.

22. At eleven-year cycles, the Sun undergoes changes in A. rotational direction. • magnetic field reversal. • layer composition. • all of the above. Comment: The magnetic field reversals are related to the number of sunspots.

23. Which planet has the most pronounced system of planetary rings? A. Mars. • Jupiter. • Saturn. D. Uranus.

24. Which planet has the most pronounced system of planetary rings? A. Mars. • Jupiter. • Saturn. • Uranus.

25. Which of these planets has a system of planetary rings? A. Neptune. • Uranus. • Both of the above. D. Neither of the above.

26. Which of these planets has a system of planetary rings? A. Neptune. • Uranus. • Both of the above. • Neither of the above.

27. Comets are composed mostly of A. iron. • ice and rock. • hydrogen and helium. D. silicon.

28. Comets are composed mostly of A. iron. • ice and rock. • hydrogen and helium. • silicon.

29. Which of these makes contact with Earth’s surface? A. Meteor. • Meteorite. • Meteoroid. D. None of the above.

30. Which of these makes contact with Earth’s surface? A. Meteor. • Meteorite. • Meteoroid. • None of the above.

31. The planet with the lowest density is A. Mars. • Neptune. • Uranus. D. None of the above.

32. The planet with the lowest density is A. Mars. • Neptune. • Uranus. • none of the above. Comment: It is said that Uranus could float in a giant bathtub, because the density of Uranus is less than the density of water.

33. The planet most similar to Earth in composition is A. Mercury. • Venus. • Mars. D. Neptune.

34. The planet most similar to Earth in composition is A. Mercury. • Venus. • Mars. • Neptune.

35. Which was discovered first, Neptune, Uranus, or Pluto? A. Neptune. • Uranus. • Pluto. D. Actually, they were all discovered in the same year.

36. Which was discovered first, Neptune, Uranus, or Pluto? A. Neptune. • Uranus. • Pluto. • Actually, they were all discovered in the same year. Explanation: Recall that perturbations in Uranus that led to the discovery of Neptune and later Pluto.

37. Which of these planets has one or more moons? A. Earth. • Jupiter. • Uranus. D. All of the above.

38. Conceptual Integrated Science—Chapter 27 Which of these planets has one or more moons? A. Earth. • Jupiter. • Uranus. • All of the above.

39. Which is farthest from the Sun? A. Pluto. • Asteroid Belt. • Kuiper Belt. D. Oort Cloud.

40. Which is farthest from the Sun? A. Pluto. • Asteroid Belt. • Kuiper Belt. • Oort Cloud.

41. Pluto’s status as a planet is controversial, because A. its orbit is highly inclined compared with those of the planets. • its composition doesn’t match any of the other planets. • it spends much of its time with comets in the Kuiper Belt. D. all of the above.

42. Pluto’s status as a planet is controversial, because A. its orbit is highly inclined compared with those of the planets. • its composition doesn’t match any of the other planets. • it spends much of its time with comets in the Kuiper Belt. • all of the above.

43. During the time of a new moon, A. the Sun is between Earth and the Moon. • Earth is between the Sun and Moon. • a solar eclipse is possible. D. none of the above.

44. During the time of a new moon, A. the Sun is between Earth and the Moon. • Earth is between the Sun and Moon. • a solar eclipse is possible. • none of the above. Explanation: A new moon is in the daytime sky, between Earth and the Sun. When it is exactly between, we have a solar eclipse. A full moon, on the other hand, occurs when Earth is between the Sun and Moon. At that time, we see the Moon fully in sunshine.

45. During the time of a full moon, the A. Sun is between Earth and the Moon. • Moon is between the Sun and Earth. • Earth is between the Sun and Moon. D. none of the above.

46. During the time of a full moon, the A. Sun is between Earth and the Moon. • Moon is between the Sun and Earth. • Earth is between the Sun and Moon. • none of the above. Explanation: A full moon occurs when Earth is between the Sun and Moon, when in Earth’s view, the Moon is fully illuminated with sunshine. When Earth is exactly between the Sun and Moon, we have a lunar eclipse.

47. The Moon’s eroding agents have been A. wind and storms. • plentiful water in its past. • meteoroid impacts. D. all of the above.

48. The Moon’s eroding agents have been A. wind and storms. • plentiful water in its past. • meteoroid impacts. • all of the above. Explanation: The Moon is too small to hold an atmosphere, so winds and storms are not part of its history. Although there is evidence of some ice at the Moon’s poles, there is no evidence of plentiful water in its history. Meteoroid impacts have not been covered, as they have on bodies having an atmosphere. The Moon wears no make-up.

49. Only one hemisphere of the Moon continually faces Earth, because the Moon A. doesn’t rotate about an internal axis. • experiences a torque when not aligned with the Earth’s magnetic field. • experiences a torque when not aligned with the Earth’s gravitational field. D. all of the above.

50. Only one hemisphere of the Moon continually faces Earth, because the Moon A. doesn’t rotate about an internal axis. • experiences a torque when not aligned with the Earth’s magnetic field. • experiences a torque when not aligned with the Earth’s gravitational field. • all of the above.