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 the change in binding energy per nucleon with nucleon number $A$ for $A$ values from $1$ to $250$.

(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 $\left(^{93}_{38}\text{Sr}\right)$ and xenon-139 $\left(^{139}_{54}\text{Xe}\right)$ according to $^{1}_{0}\text{n} + Z \rightarrow ^{93}_{38}\text{Sr} + ^{139}_{54}\text{Xe} + 2\,^{1}_{0}\text{n}$. Table 9.1 gives the binding energies of the strontium-93 and xenon-139 nuclei. The fission of $1.00\,\text{mol}$ of $Z$ releases $1.77 \times 10^{13}\,\text{J}$ of energy. 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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