(a)[1]
State what is meant by nuclear fusion.
(b)
In the D-T reaction, a deuterium ($^{2}_{1}\text{H}$) nucleus fuses with a tritium ($^{3}_{1}\text{H}$) nucleus to produce a helium-4 ($^{4}_{2}\text{He}$) nucleus. The nuclear equation for the reaction is $^{2}_{1}\text{H} + {}^{3}_{1}\text{H} \rightarrow {}^{4}_{2}\text{He} + {}^{1}_{0}\text{n} + \text{energy}$. Figure 9.1 gives some data for this reaction.
(b(i))[3]
Calculate the energy, in $\text{MeV}$, equivalent to $1.00\,\text{u}$. Explain your working.
(b(ii))[2]
Use data from Fig. 9.1 and your answer in (i) to determine the energy released in this D-T reaction.
(b(iii))[2]
Suggest why, for the D-T reaction to take place, the temperature of the deuterium and the tritium must be high.