NAME:___________________________________
 
THIRD EXAM
 APAS 1020 SECTION 001

DO ALL 19 PROBLEMS. MARK YOUR ANSWERS ON THIS SHEET AND TURN IT IN.
Multiple Choice are worth 4 points each.

c=3x1010 G=6.7x10-8 h=6.6x10-27 s =5.7x10-5
1pc=3x1018cm 1AU=1.5x1013cm M¤ =2x1033g R¤ =7x1010cm
   F=ma  x=vt v=at
    

_____ 1. A classical nova always involves which kind of star?
a. main sequence b. O or B star c. white dwarf d. neutron star e. black hole

_____ 2. What is the primary energy source for heating of the interstellar medium?
a) cosmic rays
b) O stars
c) supernova remnants
d) molecular clouds
e) neutron stars
 
_____ 3. An HII region is:
a) a region of space ionized by an O or B star.
b) a stellar wind
c) a region of dense molecular hydrogen
d) a region of anomalous Hubble flow
e) a gas cloud trapped in a cluster of galaxies
 
_____ 4. The missing (or invisible) mass:
a)is the dominant form of matter in the universe.
b)binds clusters of galaxies together
c)causes flat rotation curves for galaxies
d)stabilizes galactic disks
e)all of these
 
_____ 5. The largest member of the Local Group is:
a) Milky Way b)Large Magellanic Cloud c) M31 d) M33 e) M87
 
_____ 6. The Magellanic Clouds:
a) Orbit the the Milky Way
b) Are spiral galaxies
c) Are dim, dying galaxies
d) All of these
e) none of these
 
_____ 7. The galaxy drawn to the right would best be
classified as: a)E0 b)E7 c)S0 d)Sb e)SBc

_____ 8. The galaxy drawn to the right would best be
classified as: a)E0 b)E7 c)S0 d)Sb e)SBc

_____ 9. The Milky Way is classified as:
a)E0 b)E7 c)S0 d)Sb e)SBc

_____ 10. In the energy conserving phase (II), a supernova remnant:
a)radiates in the x-rays
b)retains most of its initial energy
c)may be many parsecs in diameter
d)all of the above
e)none of the above
 
_____11. How many stars are there in a typical globular cluster?
a)thousand b)million c)billion d)trillion e)quadrillion
 
_____12. How many stars are there in a typical large spiral galaxy?
a)thousand b)million c)billion d)trillion e)quadrillion
 
13. (7 pts) Draw a schematic of the Milky Way viewed edge on. Show and label the major components of the galaxy. Show the approximate position of the Sun.
 

14. (7pts) What are Superbubbles and the Galactic Fountain?
 
 

15. (7 pts) Draw and label the Hubble Sequence of galaxies.
 
 

16. (7pts) Given that the Schwarzschild Radius for the Sun (M=2x1033g) is 3km and the Schwarzschild radius is proportional to mass, calculate the Schwarzschild Radius for the Earth (mass =2x1027g ).
 
 

17. (8 pts) A 10,000km radius white dwarf star is spinning every 10 seconds. Calculate the speed of a point on its equator, and compare it with the speed of light.

 
 

18. (8pts) Explain why an HII region appears red in the visible part of the spectrum.

 
 

19. (8pts) What causes a classical nova?

answers: 1c, 2c, 3a, 4e, 5c, 6a, 7-, 8-, 9d, 10d, 11b, 12d