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Nuclear Physics. The Nucleus: Back to Rutherford. Rutherford. the nucleus. Notation A X Z. Atomic number. e.g. 55 Fe 26 A=55, Z=26, N=29. Atomic mass. All Stable Nuclei are composed of a. protons and electrons. b. protons and neutrons. c. neutrons and electrons. d. only protons.
E N D
The Nucleus: Back to Rutherford Rutherford
the nucleus Notation AXZ Atomic number e.g. 55Fe26 A=55, Z=26, N=29 Atomic mass
All Stable Nuclei are composed of a. protons and electrons. b. protons and neutrons. c. neutrons and electrons. d. only protons. e. only neutrons.
Isotopes and Isobars • Isotopes – different number of neutrons • Carbon comes in types • Carbon-12 (Z=6,A=12,N=6) • Carbon-14 (Z=6, A=14, N=8) • Isobars – different elements, same A • e.g. • Carbon-14 (Z=6,A=14,N=8) (radioactive) • Nitrogen-14 (Z=7,A=14,N=7) (stable) • Oxygen-14 (Z=8,A=14,N=6) (radioactive)
Units of mass • Mass • kg • MeV/c2 Using E=mc2 • Amu (or u) 1/12 m(12C) • includes electron • 1u=931.49 MeV/c2 • = 1.6605x10-27kg
Binding Energy E=mc2 matom H
The charge on the neutron is a. the same as the charge of the proton. b. zero. c. half the proton charge. d. proportional to the square of the nuclear radius. e. twice the proton charge.
Binding energy is negative(but written as a positive quantity) most stable
Fission Fig 45-2a, p.1482
The chain reaction Fig 45-3, p.1483
Chain reaction chainreaction
controlling it Fig 45-6, p.1486
Fusion and power Fig 45-14, p.1494
Squeeze it Princeton Plasma Physics Lab Fig 45-10a, p.1491
ITER Fig 45-11, p.1492
blow it up National Ignition Facility (NIF) Livermore Fig 45-12, p.1493
Why neutronsspacers and glue Nuclear binding
15. How does the rest energy of a nucleus compare to the sum of the rest energies of the individual nucleons when apart from the nucleus? a. It is greater than the sum. b. It is less than the sum. c. It is equal to the sum. d. It is in the ratio of 1:1.25. e. It is in the ratio of 1:1.1.