Download Astr40 HWII - Empyrean Quest Publishers

ASTRONOMY 40—HOMEWORK II (New)
1. All of Newton's notions of space and time are adequate to handle motion at all speeds.
A. True B. False
2. General Relativity gives us a new perspective on the force of Gravity.
A. True B. False
3. Events happening at the same time (simultaneous) in one frame of reference are simultaneous
in all frames of reference.
A. True B. False
4. In the PowerPoint on Space and Time, it says that the laws of physics and the speed of light
are the same for everyone. This is not true. (Do Googling research.) It is only true for observers
A. in accelerated motion. B in inertial motion at a constant speed or at rest.
C. at rest. D. on the earth.
5. There is a speed limit in the universe. It is the speed of light and holds only for entities
A. with mass B. without mass, like light. C. like fields. D. accelerated slowly.
6. If I shine a flashlight forward on a spacecraft moving at 1/2 c (the speed of light), an observer
at rest will observe the light to move
A. 1 1/2 c. B. c. C. 1/2 c.
7. In the Special Theory of relativity time is slowed down (time dilation) a lot for an observer
A. at rest. B. moving a lot more slowly.
C. a rapidly moving observer.
8. The famous formula specifying that mass can be converted into light energy and vice versa,
E = mc(squared), can be derived from
A. Newton's Laws.
B. the formula for addition of velocities.
C. the formula for mass increase for a rapidly moving body.
9. The universe could have a finite volume.
A. True B. False
10. Spacetime for the universe is unique.
A. True B. False
11. The shortest path through spacetime from one place to another also takes the shortest time.
A. True B. False
12. An object's path through spacetime is called its
A. worldline. B. world track. C. spaceline. D. geodesic.
13. The flat and saddle-shaped universe are _____ in extent.
A. finite B. infinite
C. finite in one direction, infinite in another.
14. What is nearly infinite near the very center of a black hole?
A. Mass B. Gravity C. The speed of light
15. Gravitational time dilation in General Relativity says which clock runs faster?
A. A clock on Mount Everest. B. A clock at sea level on the earth
C. A clock near the event horizon of a black hole.
16. The reason the twin paradox is not reversible is that the twin who goes to the distant star
A. is not accelerating. B. is accelerating. C. is an inertial observer.
17. An electron in an atom can have any energy in its orbit.
A. True B. False
18. An equal amount of matter and antimatter may annihilate and produce pure energy or light.
A. True B. False
19. A Fermion is a particle with integer spin like the photon.
A. True
B. False
20. In describing the nuclear force, neutron and protons are made up of three
A. electrons. B. quarks. C. bosons.
21. An electron is in which family of particles?
A. quarks B. leptons C. partons D. baryons
22. Neutrinos, have a _________ mass, no charge, and interact very seldom with matter.
A. large B. small C. non-existent
23. In quantum theory, a particle can be described
A. only like a billiard ball with a definite location. B. by a wave of probability.
C. as a probability wave packet. D. both 2 and 3 might fit.
24. Two of these particles cannot occupy the same state at the same time (described by the same
quantum numbers). This is called the Pauli Exclusion Principle.
A. Bosons B. Fermions C. Photons
25. If chemistry alone were producing the sun's energy it couldn't last more than roughly 10,000
years.
A. True B. False
26. The sun is the size it is because inward pull of gravity is balanced by outward electric
repulsion. A. True B. False
27. Sunspots are cooler than other regions of the sun's surface, but have stronger magnetic fields.
A. True B. False
28. The stronger the magnetic field in a region of the sun, the more certain spectral lines split to
different energies. This relationship is call the
A. magnetic split.. B. Zeeman effect. C. Helmholtz contraction.
29. From the PowerPoint, the year with the greatest solar activity (most sunspots) in the last
hundred years was:
A. 1947 B. 1959
C. 2002
30. Solar flares are caused by increase in A. magnetic activity.
core. C. the sun's rapid rotation. D. the solar wind.
B. nuclear fusion in the sun's
31. The convection zone of the sun operates by
A. randomly bouncing photons gradually allowing energy to escape.
B. hot portions of gas rising to the surface, and cool ones falling.
C. heat transfer by contact of molecules.
32. The reason for the low number of detections of which solar particle (at earth) was under
dispute for a long time?
A. gamma rays B. electrons C. neutrinos
33. The apparent brightness of a star depends on both its luminosity and distance.
A. True B. False
34. If you could move the sun twice as far away from the earth, it would have half the apparent
brightness. A. True B. False
35. The parallax shift of all stars (except the sun) is less than an arcsecond, because one
arcsecond of parallax corresponds to a distance of one parsec (3.2 LYR), and all stars are farther
away. Closest is Alpha Centauri at 4.37 LYR.
A. True B. False
36. The hotter the star, the larger the peak or brightest wavelength of the thermal or black body
radiation of its surface.
A. True B. False
37. The temperature of the surface of the sun (the photosphere) is about
B. 5,800 K C. 12,500 K
D. 20,000 K
A. 3,000 K
38. The more ionized the gases are in the surface of a star the _________ the temperature.
A. higher B. lower C. They are the same temperature with different ionization.
39. A star with spectral type G like the sun, has its peak or brightest color as (look at chart in
power points--don't just guess) A. Yellow B. Blue Green C. Red
40. For an object orbiting in a circle, if we know its orbital period p, we can get the mass of the
thing it's orbiting by also measuring its
A. just orbital speed.
B. just orbital radius. C. Both 1 and 2 necessary. D. Either 1 or 2.
41. Can an object with a mass of 5% of the sun's become a star? A. Yes B. No
C. Maybe, if it contracts enough.
42. Matter in clouds that form stars in mostly monatomic, not in molecules.
A. True B. False
43. Carbon monoxide (CO) spectral lines tells us some of what we know about star-forming
clouds.
A. True B. False
44. Interstellar dust scatters blue light more than red light.
A. True
B. False
45. We cannot see stars in any wavelength through a dense, but moderate-sized dust cloud.
A. True B. False
46. Newborn stars are often invisible in visible light, because they gather a cloud of _______
around them
A. gases like H and He B. dust C. planetesimals
D. rocks
47. The minimum mass for a dense molecular cloud to start forming stars is roughly
A. a few solar masses B. about 10 solar masses
C. a few hundred solar masses D. a few thousand solar masses
48. The outward resistance to the inward pull of gravity, as a cloud starts to collapse to form a
star, comes from
A. outward pressure due to emission B. magnetic field
C. gas turbulence D. all the above
49. Stars formed early in the universe were, on the average, ____________ than stars forming
now. A. more massive B. less massive D. in the same mass ranges
50. Before it kindles nuclear fusion as star is called
C. a baby star
A. an embryonic star
B. a protostar