(a)[2]
State Coulomb’s law in words.
(b(i))[2]
Explain how the electric force between the electron and the positron makes the moving particles travel in a circular path.
(b(ii))[2]
Show that the magnitude of the electric force between the electron and the positron comes to $2.28 \times 10^{-9}\,\text{N}$.
(b(iii))[3]
Use the data in (b)(ii) to determine the period of the two particles’ circular orbit.
(c(i))[3]
Describe how the two particles in positronium produce gamma radiation.
(c(ii))[1]
State one medical application that uses the process described in (c)(i).