Explain what is meant by the nuclear binding energy of a nucleus.
State the value of the binding energy of a 01n^{1}_{0}\text{n}01n nucleus (a free neutron) and suggest why it has this value.
In some stars (such as young brown dwarfs), a key fusion reaction in the core is:
13H+13H→24He+2 01n ^{3}_{1}\text{H} + {}^{3}_{1}\text{H} \rightarrow {}^{4}_{2}\text{He} + 2\,{}^{1}_{0}\text{n} 13H+13H→24He+201nThe average nuclear binding energy per nucleon for 13H^{3}_{1}\text{H}13H is 2.8 MeV2.8\text{ MeV}2.8 MeV and for 24He^{4}_{2}\text{He}24He is 7.2 MeV7.2\text{ MeV}7.2 MeV.
Calculate the energy released in a single fusion event of this type, in joules.
A brown dwarf undergoing this reaction as its primary source of energy decreases in mass by 5.4×107 kg5.4 \times 10^7\text{ kg}5.4×107 kg every second. Under the assumption that this mass loss is solely due to this fusion process, calculate the number of these fusion events occurring in the brown dwarf per second.
In the CNO cycle of a massive star, the following decay occurs as a key step:
713N→613C+10β++Y ^{13}_{7}\text{N} \rightarrow {}^{13}_{6}\text{C} + {}^{0}_{1}\beta^+ + \text{Y} 713N→613C+10β++YIdentify the missing particle Y\text{Y}Y and state its electric charge.
Determine the total number of down quarks present in the reactant nucleus at the start of this decay.
Write down the equation for this reaction at the fundamental level in terms of quarks.
90 exam-style questions on OCR A A Level Physics Nuclear and particle physics, covering The nuclear atom, Fundamental particles, Radioactivity, and Nuclear fission and fusion. Each one has a worked solution and a mark scheme showing where the marks go.