(a(i))[1]
Use the quark model to demonstrate that a proton has charge $+e$.
(a(ii))[1]
Use the quark model to demonstrate that the charge on a neutron is zero.
(b(i))[1]
A nucleus of $^{90}_{38}\text{Sr}$ undergoes $\beta^-$ decay, with a $\beta^-$ particle emitted. A nucleus of $^{64}_{29}\text{Cu}$ undergoes $\beta^+$ decay, with a $\beta^+$ particle emitted. In Fig. 7.1, state the nucleon number and proton number for the nucleus formed in each decay process.
(b(ii))[1]
State the name of the force that is responsible for $\beta$ decay.
(b(iii))[1]
State the names of the leptons produced in each decay process. $\beta^-$ decay: $\beta^+$ decay: