What are the differences between a proton, a positron and a photon? You can describe how their masses differ, how their charges differ or whether they are

particles or antiparticles.

Which of the interactions is not possible?

(a) ${}_2{}^4\mathrm{He}+{}_0{}^1\mathrm{n}\to {}_2{}^5\mathrm{He}$

(b)  ${}_{84}{}^{209}\mathrm{Po}\to {}_{82}{}^{205} \mathrm{Pb}+{}_2{}^4\alpha$

(c)  ${}_8{}^{14}\mathrm{O}\to {}_7{}^{14} \mathrm{N}+{}_1{}^0\beta +{}_0{}^0\nu$

(d) ${}_{14}{}^{31}\mathrm{Si}\to {}_{15}{}^{31} \mathrm{N}+{}_{-1}{}^0\beta +{}_0{}^{0}v$

Hadrons are made up from quarks.

Which combination of quarks could make up a meson?

(a) $\mathrm{dd}\overline{\mathrm{s}}$

(b) $\mathrm{ssc}$

(c) $\mathrm{s}\overline{\mathrm{b}}$

(d) $\mathrm{sc}$