(a) Radioactive sodium has a nuclide represented by the symbol
Complete the equation below to show how this nuclide decays with the emission of a β-particle.
(b) The figure below shows a narrow beam of β-particles entering an electric field created by two charged plates.
(i) Complete the path of the β-particles, starting from the point P.
(ii) Explain any change of direction which you have shown.
(c) (i) In the space below, draw a labeled diagram of an arrangement, using a radioactive source which emits β-particles, for finding the variation in thickness of a sheet of paper.
(ii) State the readings which need to be taken and how they would be used to decide whether or not the thickness of the paper varies.