DP Physics (last assessment 2024)

Question 19M.2.HL.TZ1.2a.ii

Date	May 2019	Marks available	[Maximum mark: 2]	Reference code	19M.2.HL.TZ1.2a.ii
Level	HL	Paper	2	Time zone	TZ1
Command term	Estimate	Question number	a.ii	Adapted from	N/A

a.ii.

[Maximum mark: 2]

19M.2.HL.TZ1.2a.ii

A beam of electrons each of de Broglie wavelength 2.4 × 10^–15 m is incident on a thin film of silicon-30 $\left( {{}_{14}^{30}{\text{Si}}} \right)$ . The variation in the electron intensity of the beam with scattering angle is shown.

(a.ii)

Estimate, using the result from (a)(i), the nuclear radius of thorium-232 $\left( {{}_{90}^{232}{\text{Th}}} \right)$ .

[2]

Markscheme

R_Th = R_si ${\left( {\frac{{{A_{{\text{Th}}}}}}{{{A_{{\text{Si}}}}}}} \right)^{\frac{1}{3}}}$ or substitution ✔

7.4 «fm» ✔

Examiners report

This question was also left blank by many candidates. Many who did answer simply used the ratio of the of the mass numbers of the two elements and failed to take the cube root of the ratio. It should be noted that the question specifically stated that candidates were expected to use the result from 2ai, and not just simply guess at the new radius.

Syllabus sections

Additional higher level (AHL)

Additional higher level (AHL) » Topic 12: Quantum and nuclear physics » 12.2 – Nuclear physics

Additional higher level (AHL) » Topic 12: Quantum and nuclear physics

Question 19M.2.HL.TZ1.2a.ii

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