A nucleus of phosphorus-32 \(\left( {{}_{15}^{32}{\rm{P}}} \right)\) decays by beta minus (β⁻) decay into a nucleus of sulfur-32 \(\left( {{}_{16}^{32}{\rm{S}}} \right)\). The binding energy per nucleon of \({{}_{15}^{32}{\rm{P}}}\) is 8.398 MeV and for \({{}_{16}^{32}{\rm{S}}}\) it is 8.450 MeV.

Determine the energy released in this decay.

The graph shows the variation with time t of the activity A of a sample containing phosphorus-32 \(\left( {{}_{15}^{32}{\rm{P}}} \right)\).

Determine the half-life of \({{}_{15}^{32}{\rm{P}}}\).

Quarks were hypothesized long before their existence was experimentally verified. Discuss the reasons why physicists developed a theory that involved quarks.

quark theory is simpler OR Occam’s razor example OR simple model explains complex observations

quotes experiment that led to quark theory, eg deep inelastic scattering or electron scattering

model incorporates strong/weak interactions/forces between protons and neutrons

model incorporates conservation rules

model explains differences between neutrons and protons OR explains decay of neutron to proton