All more-or-less Conceptual Questions:
1. Explain how the observed expansion of the universe leads to a determined age for the universe.
2. What are the most elementary particles and forces?
3. Which property of particles does each force interact with?
4. Which particle in the free state is least stable?
a. electron
b. neutrino
c. neutron
d. proton
5. Which of the following forces is the weakest?
a. strong nuclear
b. weak nuclear
c. electromagnetic
d. gravitational
6. A positron and an electron differ in:
a. charge.
b. mass.
c. spin.
d. energy.
7. According to present theories, there is a neutrino for all the following particles except:
a. neutral pion.
b. electron.
c. muon.
d. tau lepton.
8. What quantity is conserved in the following reaction?
n decays to p+ + e- +
anti-neutrinoe
a. baryon number
b. charge
c. lepton number
d. all of the above
9. Experimentally, strange particles can be produced in abundance but they decay relatively slowly. This occurs because strangeness:
a. is conserved in both their production and decay.
b. is conserved in their production but not in their decay.
c. is conserved in their decay but not in their production.
d. is not conserved in either their production or their decay.
10. The S+, S0, and S- all have strangeness of (-1). The collision of an anti-proton and a neutron may produce which of the following particles? (HINT: use number conservation laws)
a. S- and S0
b. S+ and anti-S0
c. anti-S+ and S0
d. anti-S- and S0
11. If two quarks in an anti-proton have the color anti-red and anti-blue, the third quark must have the color:
a. red.
b. blue.
c. anti-purple.
d. anti-green.
12. The charge on some quarks or anti-quarks is:
a. 0.
b. 1/2 (1.6 x10-19) C.
c. 1/3 (1.6 x10-19) C.
d. 1 (1.6 x10-19) C.
13. The force that acts between an electron and a quark in beta decay is caused by the exchange of:
a. photons.
b. gluons.
c. gravitons.
d. W+, W-,
and Z0 bosons.
14. The sun has mass 2 x1030 kg, of which 0.75 was hydrogen at the beginning of its "life". About 0.13 of this hydrogen is available as nuclear fuel at the center where it is hot enough to react. The reaction converts 4 protons into a helium nucleus. The mass of one proton is 1.0073 u (1 u = 1.66 x10-27 kg), and the mass of one helium nucleus is 4.0005 u. For how long will the sun last, radiating a luminosity of 4 x1026 W?
ans: 10 billion years
find binding energy per initial proton (comes out to 0.007 of initial
mass). then 0.007x0.75x0.13 of mass can convert to energy.
15. Stars are arranged in large groups called:
a. clusters.
b. sheets.
c. galaxies.
d. voids.
16. What is the cosmic background radiation?
a. Gamma rays from distant quasars.
b. Microwaves cooled from the hot Big Bang.
c. Ultraviolet from distant stars.
d. Infrared from warm dust everywhere.
17. Where did the carbon in our bodies come from?
a. Nuclear reactions in the Sun.
b. Ancient forest fires.
c. Photosynthesis in plants.
d. Nuclear reactions in previous stars.
18. What is the evidence for so-called "dark matter"?
a. More gravity than can be accounted for by visible matter.
b. Shading of distant stars.
c. Occasional eclipses of galaxies.
d. Non-conservation in certain high-energy particle experiments.
19. Which of the following forces is most likely the carrier of consciousness?
a. strong nuclear
b. weak nuclear
c. electromagnetic
d. gravitational