(a(i))[3]
Complete the equation for the decay shown. $^{208}_{81}\text{Tl} \rightarrow \; \dots\dots\text{Pb} + \dots\dots\beta$
(a(ii))[1]
Explain why $\gamma$-emission has no effect on the numbers in the equation in (a)(i).
(a(iii))[1]
Suggest one cause of the instability of a thallium-208 nucleus.
(b)[3]
The narrow beam enters a region where the magnetic field points into the page. On Fig. 8.1: • draw a line labelled $\beta$ to show the route followed by the $\beta$-particles in the magnetic field • draw a line labelled $\gamma$ to show the route followed by the $\gamma$-radiation in the magnetic field.