DP Physics (last assessment 2024)

Question 21N.2.SL.TZ0.b.ii

b.ii.

[Maximum mark: 2]

21N.2.SL.TZ0.b.ii

Plutonium-238 (Pu) decays by alpha (α) decay into uranium (U).

The following data are available for binding energies per nucleon:

plutonium 7.568 MeV

uranium 7.600 MeV

alpha particle 7.074 MeV

The plutonium nucleus is at rest when it decays.

Calculate the ratio $\frac{kinetic energy of alpha particle}{kinetic energy of uranium}$ .

[2]

Markscheme

« $\frac{K E_{α}}{K E_{U}} =$ » $\frac{\frac{p^{2}}{2 m_{α}}}{\frac{p^{2}}{2 m_{U}}}$ OR $\frac{m_{U}}{m_{α}}$ ✓

« $\frac{234}{4} =$ » $58.5$ ✓

Award [2] marks for a bald correct answer.

Accept $\frac{117}{2}$ for MP2.

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