h133_finalprep

h133_finalprep - What you should know about ... Nuclear...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: What you should know about ... Nuclear Physics 1. Nuclei and strong interaction [Q12,Q13] nuclear notation: Z protons and A total nucleons = A Z X ; size: r = r A 1 / 3 , with r 1 . 2fm Strong interaction between color neutral objects (such as nucleons) is short range ( < 2fm) Binding energy: E b = ( parts E parts )- E sys Mass defect: m = ( parts m parts )- m sys = E b /c 2 = Zm H + Nm n- m atom binding energy formula ( A > 20): E b ( A,Z ) = a I A- a S A 2 / 3- a C Z 2 /A 1 / 3- a A ( A- 2 Z ) 2 /A with a I = 15 . 56MeV, a S = 17 . 23MeV, a C = 0 . 697MeV, a A = 23 . 285MeV binding energy per nucleon, e b = E b /A and binding energy vs. mass ( E = mc 2 ) 2. Radioactive decay (beta, alpha, gamma) [Q13,Q14] Predicting stability and type of decay: energy level diagrams, binding energy formula, atomic mass beta: - = n- p + + e- + e + = p +- n + e + + e EC = p + + e-- n + e alpha: helium nuclei (2 protons, 2 neutrons) gamma: photons from decays of excited nuclear states activity - dN/dt = N = solution: N ( t ) = N e- t = half-life t 1 / 2 = ln2 / Z stable ( A ) for stability against decay: Z stable = A 1 . 0084 2+0 . 015 A 2 / 3 . This formula gives the stable isotope for even-odd nuclei ( A is odd) or even-even nuclei (both Z stable and N are even). For odd-odd nuclei ( A even, N,Z stable odd) the neighboring even-even nuclei may have lower atomic mass, in which case the stable nuclei have Z = Z stable 1....
View Full Document

Page1 / 3

h133_finalprep - What you should know about ... Nuclear...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online