Questions
Question 1
*
What condition on \(Q\) is required for a decay to be energetically spontaneous?
Question 2
*
In \(\alpha\) decay, how do \(A\) and \(Z\) change?
Question 3
*+
In \(\beta^-\) decay, how do \(A\), \(Z\), and \(N\) change?
Question 4
*+
In \(\beta^+\) decay, how do \(A\), \(Z\), and \(N\) change?
Question 5
**
A nucleus is neutron-rich compared with stable nuclei of similar \(A\). Which beta decay mode tends to move it toward stability?
Question 6
**
A proton-rich nucleus is unstable. Which process can move it toward a larger neutron fraction?
Question 7
**
Balance the alpha decay \(^{238}_{92}\mathrm U\to ?+\alpha\).
Question 8
**
Balance the beta-minus decay of \(^{14}_{6}\mathrm C\).
Question 9
*
Why does gamma emission usually not change \(A\) or \(Z\)?
Question 10
**+
A proposed decay has \(m_i=10.0000\,\mathrm u\) and \(m_f=10.0020\,\mathrm u\). Find \(Q\) and decide if it is spontaneous.
Question 11
***
Why are very heavy nuclei often alpha emitters?
Question 12
***
Explain why beta decay can occur even though the mass number \(A\) does not change.
Question 13
***+
Why is high binding energy per nucleon related to stability but not a complete stability criterion?
Question 14
***
A nucleus has too many neutrons. Explain how \(\beta^-\) decay changes \(N/Z\).
Question 15
***
A nucleus has too many protons. Explain why electron capture can compete with \(\beta^+\) decay.
Question 16
***+
Why must a neutrino or antineutrino be included in beta decay?
Question 17
***
A decay chain has two alpha decays followed by one beta-minus decay. Find the net changes in \(A\) and \(Z\).
Question 18
****
Using atomic masses, why does \(\beta^+\) decay require more mass excess than electron capture?
Question 19
****
Explain why a decay with \(Q>0\) may still have a very long half-life.
Question 20
*****
Prove that \(\beta^-\) decay conserves charge and nucleon number at the nuclear level.