29.1. Appendix A: Answers to Selected Problems (3e) http://www.ck12.org
Ch 21: Radioactivity and Nuclear Physics
1..
2..
3..
4..
5..
- SubstanceAdecays faster thanB
- SubstanceBbecause there is more material left to decay.
1.^21988 Ra→^21586 Rn+^42 He
2.^15863 Eu→^15864 Gd+^0 − 1 e−
3.^5322 Ti→^5323 Va+^0 − 1 e−
4.^21183 Bi→^20781 Tl+^42 He - 5× 1024 atoms
- Decay of a lot of atoms in a short period of time
- 5 × 1024 atoms
4.^12
- 5 × 1024 atoms
- 26.6 minutes
- The one with the short half life, because half life is the rate of decay.
- SubstanceB= 4 .6 g and substanceA= 0 .035 g
- substanceB
- 1.2 g
- 125 g
- 0.46 minutes
10.t= 144 ,700 years - 0.0155 g
- 17 years
- 49,000 years
Ch 22: Standard Model of Particle Physics
- strange
- some type of meson
- Electron, photon, tau...
- Neutron, electron neutrino,Z^0
- Neutron, because it doesn’t have electrical charge
- No, because it doesn’t have electrical charge
- Two anti-up quarks and an anti-down quark
- Lepton number, and energy/mass conservation
- Yes,W+,W−, because they both have charge
- The weak force because it can interact with both quarks and leptons
- Yes; a,b,c,e; no; d,f
- The standard model makes verifiable predictions, string theory makes few verifiable predictions.