Cypress College ASTR 116 Homework
Astronomy 116, Homework CHAPTER 13 (A) Neutron Stars & Black
Holes. Due:
Print Last, First Name and date on the small Scantron in INK. Print
your last name in BIG BLOCK letters on the back of the Scantron.
Use a No. 2 pencil to fill out Scantron. Read the chapter.
Look at the videos and simulations in the CD-ROM. Answer all True/False and
Fill in the Blank questions. Then answer the following questions and
turn in your Scantron only. Choose the best answer.
1. X-ray bursters are caused by a process similar to that in a
- a) nova
- b) Type I supernova
- c) Type II supernova
- d) None of the above.
2. The speed of light is
- a) 186,000 km/s
- b) 300,000 km/s
- c) 300,000,000 km/s
- d) None of the above.
3. On average, black holes make the universe
- a. hotter
- b. cooler
- c. neither, they do not affect the universes temperature.
4. What compelling evidence links pulsars to neutron stars?
- a) Both pulsars and neutron stars can be found in globular star
clusters.
- b) Only a small rotating source of radiation is thought to be able
to emit precisely timed pulses such as those from pulsars.
- c) Pulsars are known to evolve into neutron stars.
- d) Both pulsars and neutron stars have been discovered near the
Sun.
5. What would happen if mass is continually added to a 1.4 solar
mass neutron star?
- a) The star's radius would increase.
- b) The star would eventually become a black hole.
- c) The star would erupt as a supernova.
- d) all of the above
- e) none of the above
6. Which of the following is not an argument for Cygnus X-1's being a true
black hole?
- a) Spectroscopic evidence suggests that hot gas is flowing from
the companion B star onto Cygnus X-1.
- b) Cygnus X-1's mass is estimated to be between 5 and 10 solar masses.
- c) The mass of the companion B star is even greater than that of
Cygnus X-1, at around 30 solar masses.
- d) X-rays from Cygnus X-1 vary on time scales as short as a millisecond.
7. Who discovered the first object that eventually became known
as a pulsar?
- a) Jocelyn Bell.
- b) Anthony Hewish.
- c) Martin Schwarzchild.
- d) Stephen Hawking.
8. Which of the following is not a property of the first discovered
pulsar (nor any other pulsar)?
- a) period of 1.34 seconds
- b) emissions only in the visible part of the spectrum
- c) each pulse consisting of a 0.01 second burst of radiation
- d) time interval between pulses is very uniform
9. X-ray bursters occur in binary star systems. What are
the two types of stars that must be present to make up such an object?
- a) two red giants
- b) a white dwarf and a main sequence star
- c) a main sequence star and a neutron star
- d) a white dwarf and an M-type giant
- e) two neutron stars
10. What is Cygnus X-1?
- a) an experimental spacecraft designed to travel close to the speed
of light
- b) a leading candidate for being a black hole
- c) a binary neutron star system
- d) a millisecond pulsar with two planets
- e) the first discovered X-ray burster
11. A black hole has a mass of 6 solar masses.
The radius of its event horizon is
- a. 3 km
- b. 6 km
- c. 9 km
- d. 18 km
- e. none of these.
12. What stops a neutron star from collapsing further under the
influence of gravity?
- a. Gas pressure
- b. electric repulsion
- c. electron degeneracy pressure
- d. neutron degeneracy pressure
- e. it is not known.
13. A tea spoon full of neutron star matter at the Earth's surface
would weigh
- a. about a pound
- b. a few tons
- c. as much as Mount Everest
- d. as much as the Earth
- e. as much as the Sun
14. The strongest magnetic fields are found near a
- a. sunspot
- b. white dwarf
- c. neutron star
- d. black hole
15. Is it possible to orbit safely around a black hole at a distance
of 10,000 km?