1. Which if these statements best describes the process of nuclear fusion?
  • A. The splitting of heavy nuclei into smaller nuclei, requiring energy
  • B. The splitting of heavy nuclei into smaller nuclei, releasing energy
  • C. The joining together of smaller nuclei into heavier nuclei, requiring energy
  • D. The joining together of smaller nuclei into heavier nuclei, releasing energy

2. In main sequence stars, where does fusion occur, and what elements are involved?

Fusion occurs... transforming...
A
 throughout the star hydrogen into helium
B
 throughout the star helium into carbon
C
 in the core hydrogen into helium
D
 in the core helium into carbon

3. Fusion requires extremely high temperatures and densities. This is because...

  • A. electron repulsion normally prevents light atoms from fusing
  • B. proton repulsion normally prevents light nuclei from fusing
  • C. atomic nuclei are very small and unlikely to collide
  • D. neutrons do not experience coulomb forces

4. Which force is responsible for holding the fused nuclei together?

  • A. gravity
  • B. electrostatic (coulomb) force
  • C. weak nuclear force
  • D. strong nuclear force

5. In a large stable main sequence star, which two forces are balanced?

Inward force Outward force
A
 gravity radiative pressure
B
 gas pressure radiative pressure
C
 gravity coulomb repulsion
D
 gas pressure coulomb repulsion

6. Here are three statements about the Sun:

I. The Sun is a main sequence star
II. The Sun will eventually form a white dwarf
III. The Sun is not massive enough to eventually form a neutron star
 

Which of these statements are true?

  • A. I and II
  • B. I and III
  • C. II and III
  • D. all three
7-9: These questions are about the evolution of massive stars. rigel supergiant star

7. Large stars evolve in a different pathway to the Sun. A very large main sequence star will swell and grow to become a supergiant, like Rigel shown above. What elements are fused in the core of these supergiants?

  • A. helium into heavier elements up to iron
  • B. helium into heavier elements up to carbon
  • C. hydrogen into heavier elements up to iron
  • D. hydrogen into heavier elements up to carbon

8. A supergiant will eventually run out of elements to fuse in the core. At this point it will create a...

  • A. supernova
  • B. white dwarf
  • C. neutron star
  • D. black hole

9. Which of the following options best describes the final end stage of a supergiant star?
(approximate masses of supergiant shown).

mass > 10 Msun mass > 30 Msun
A
 white dwarf neutron star
B
 black hole neutron star
C
 white dwarf black hole
D
 neutron star black hole

10. What can be determined from direct measurements of the spectrum of a star, without other data being required?

  • A. the mass and luminosity
  • B. the luminosity and surface temperature
  • C. the composition and surface temperature
  • D. the luminosity and composition