Physics 9702 · AS & A Level · Mass defect and nuclear binding energy

Mass defect and nuclear binding energy — practice question

(a)[2]

State what nuclear fusion means.

(b)[2]

On Fig. 9.1, sketch how binding energy per nucleon changes with nucleon number $A$ for values of $A$ between $1$ and $250$.

(c(i))[1]

On your line in Fig. 9.1, label a point $X$ that could stand for a nucleus that undergoes alpha-decay.

(c(ii))[1]

On your line in Fig. 9.1, label a point $Y$ that could stand for a nucleus that undergoes nuclear fusion.

(d)[4]

A nucleus $Z$ undergoes nuclear fission to produce strontium-93 $^{93}_{38}\text{Sr}$ and xenon-139 $^{139}_{54}\text{Xe}$, as shown by $^{1}_{0}\text{n} + Z \rightarrow {}^{93}_{38}\text{Sr} + {}^{139}_{54}\text{Xe} + 2\,^{1}_{0}\text{n}.$ Table 9.1 lists the binding energies of the strontium-93 and xenon-139 nuclei. When $1.00\,\text{mol}$ of $Z$ fissions, $1.77 \times 10^{13}\,\text{J}$ of energy is released. Determine the binding energy per nucleon, in $\text{MeV}$, of $Z$.

Worked solution & mark scheme

This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: Two small nuclei combine

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