Question 1

Paper 2Hard10 marks

Figure 1 shows two fission channels with the same products. The masses shown are atomic masses; the electron numbers balance in each reaction. The incident neutron’s kinetic energy is 0.025 eV0.025\ \text{eV} Use 1 u c2=931.5 MeV1\ \text{u}\,c^2=931.5\ \text{MeV}

spontaneous fission23692U14054Xe+9438Sr+10n+10n236.045568 u139.921640 u93.915356 u1.008665 u1.008665 uneutron-induced fission10n+23592U14054Xe+9438Sr+10n+10n1.008665 u235.043930 u139.921640 u93.915356 u1.008665 u1.008665 ukinetic energy0.025 eV
(a)

Calculate the energy released in the spontaneous fission reaction shown in Figure 1, in MeV.

[3]
(b)

Calculate the energy released in the neutron-induced fission reaction shown in Figure 1, in MeV.

[3]
(c)

A student claims that the greater energy release calculated for neutron-induced fission is supplied by the incident neutron’s kinetic energy. Assess this claim using Figure 1 and your answers. Include a quantitative comparison and account for the difference between the two energy releases.

[4]

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