Physics 5
Introduction to Astronomy

H. E. Smith Spring 2007

  Physics 5 - Quiz #5

Quiz 5 Answer Key

Physics 5 – Spring Quarter 2007

Prof. Smith

1. Which event marks the beginning of a supernova?

A. The sudden collapse of an iron core into a compact ball of neutrons.

B. The onset of helium burning after a helium flash.

C. The sudden initiation of the CNO cycle.

D. The beginning of neon burning in an extremely massive star.

 

2. A spinning neutron star has been observed at the center of a ______.

A. protostar.

B. supernova remnant.

C. planetary nebula.

D. red supergiant.

 

3. Which statement about pulsars is NOT thought to be true?

A. Pulsars are kept from collapsing by neutron degeneracy pressure.

B. Pulsars can form only in close binary systems.

C. A pulsar must have a very strong magnetic field and rotate quite rapidly.

D. All pulsars are neutron stars, but not all neutron stars are pulsars

 

4. Suppose the room in which you are sitting was magically transported off the Earth, and sent accelerating through the universe at 9.8 m/s2. Assuming your doors and windows are sealed and closed, how could you tell that you'd left the Earth?

A. You would weigh more than you do on Earth.

B. Your time would run slower than it does on Earth.

C. You'd hear a loud whooshing sound as you careened through space.

D. You couldn't --- the equivalence principle tells us that you won't be able to tell the difference.

 

5. According to general relativity, why does Earth orbit the Sun?

A. Earth orbits the Sun because a spacetime diagram shows the Sun to be a bowl-shaped dip in a rubber sheet.

B. Because the Earth and Sun are connected by a "rope-like" set of invisible, subatomic particles.

C. Because the mysterious force that we call gravity holds the Earth in orbit.

D. Earth is following the straightest path possible through spacetime, but this path happens to go around and around the Sun.

 

6. According to general relativity, how is time affected by gravity?

A. Time is not affected by gravity.

B. Time is stopped in places where gravity is strong.

C. Time runs slower in places where gravity is stronger.

D. Time runs faster in places where gravity is stronger.

 

7. Could our Sun ever undergo a nova or a white-dwarf supernova event? Why or why not?

No, because both events occur on white dwarfs in close binary systems. Even after our Sun becomes a white dwarf, such events wonÕt occur because our Sun is not part of a close binary.


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