6. What percentage of the energy emitted by a massive-star supernova is in neutrinos?
a. 1%
b. 10%
c. 50%
d. 99%

7. About how often do supernovae happen in our galaxy?
a. one every few centuries
b. 1 to 3 per century
c. 150 per century
d. 150 per year

8. What is a likely explanation for why we don't see as many supernovae in our galaxy as our models predict?
a. Many supernovae are obscured by dust, so their light never reaches us
b. They occur on the other side of the galaxy, too far away to be observed.
c. Supernovae are so short that if we aren't looking directly where the star exploded when it happens, we would miss it.
d. Like a pulsar, a supernova emits a beam of radiation. Because the beam is small, the chances of our seeing a given supernova are small.

Nucleosynthesis

9. Heavy elements such as gold, mercury, bismuth, and uranium were formed during
a. the Big Bang
b. Fusion in super-massive stars
c. S process in novae
d. R and S process in supernovae

10. Why can't steady core or shell fusion in a star create elements more massive than iron?
a. only a star more massive than 100 solar masses could do this, and such stars are unstable
b. the high temperatures in stellar interiors destroy more massive nuclei
c. nuclei heavier than iron are radioactive and fall apart quickly
d. making nuclei heavier than iron by fusion requires energy, instead of generating energy like the fusion of light elements

11. What is the difference between the R and S processes?
a. the R process adds protons to nuclei, the S process adds neutrons
b. the R process happens in red giants, the S process in supernovae
c. the R process happens in type I supernovae, the S process in type II
d. the R process adds neutrons rapidly, the S process adds them slowly