Questions for Chapter S4

1. What do we mean by the quantum realm? What is quantum mechanics?
2. What do we mean by fundamental particles? How do we investigate fundamental particles in particle accelerators? What is the standard model?
3. What is spin? What are the two basic categories of particles based on spin?
4. What are quarks and leptons? Explain why we say that quarks and leptons are subsets of the fermions.
5. List the six quarks and six leptons in the standard model. Describe the quark composition of a proton and of a neutron.
6. What are neutrinos? Why might they be important to the overall mass of the universe?
7. What is antimatter? How does a positron differ from an electron?
8. What happens when a particle and its antiparticle meet?
9. How is antimatter produced, and why is it always produced along with matter in pair production?
10. List the four fundamental forces in nature, and name the exchange particles for each.
11. Describe the relative strengths of the four forces. Why does gravity dominate on large scales, even though it is by far the weakest of the four forces?
12. The strong force is the force that holds the protons and neutrons in the nucleus together. Based on the fact that most atomic nuclei are stable, briefly explain how you can conclude that the strong force must be even stronger than the electromagnetic force, at least over very short distances.
13. What is the uncertainty principle? How is it related to the idea of wave-particle duality?
14. Describe two ways of quantifying the uncertainty principle, and give an example showing the meaning of each.
15. What do we mean by the quantum state of a particle?
16. What is the exclusion principle? What types of particles obey it?
17. What is degeneracy pressure? How does it differ from thermal pressure? How is it important in astronomy?
18. Explain why the uncertainty principle implies that the particles in a highly compressed plasma must move at very high speeds. How does this fact explain why there is a limit to the strength of degeneracy pressure? Why is this limit higher for neutron degeneracy pressure than for electron degeneracy pressure?

Decide whether the statement makes sense (or is clearly true) or does not make sense (or is clearly false). Explain clearly; not all of these have definitive answers, so your explanation is more important than your chosen answer.

19. Although there are six known types of quarks, ordinary atoms contain only two of these types.
20. If you put a quark and a lepton close together, they'll annihilate each other.
21. There's no such thing as antimatter, except in science fiction.
22. Some particle accelerators have been known to build up a huge electrical charge because of the electrons produced inside them.
23. According to the uncertainty principle, we can never be certain whether one theory is really better than another.
24. The exclusion principle describes the cases in which the uncertainty principle is excluded from being true.
25. No known astronomical objects exhibit any type of degeneracy pressure.
26. Although we speak of four fundamental forces- gravity, electromagnetic, strong, and weak -it is likely that these forces are different manifestations of a smaller number of truly fundamental forces.
27. Imagine that, somewhere in deep space, you meet a person made entirely of antimatter. Shaking that person's hand would be very dangerous.
28. Someday, we may detect radiation coming from an evaporating black hole.