DP Physics (first assessment 2025)

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Question 19M.2.HL.TZ2.a

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Date May 2019 Marks available [Maximum mark: 2] Reference code 19M.2.HL.TZ2.a
Level HL Paper 2 Time zone TZ2
Command term Suggest Question number a Adapted from N/A
a.
[Maximum mark: 2]
19M.2.HL.TZ2.a

Suggest why de Broglie’s hypothesis is not consistent with Bohr’s conclusion that the electron’s orbit in the hydrogen atom has a well defined radius.

[2]

Markscheme

«de Broglie’s hypothesis states that the» electron is represented by a wave ✔

therefore it cannot be localized/it is spread out/it does not have a definite position ✔

Award MP1 for any mention of wavelike property of an electron.

Examiners report

This question could have simply asked for the differences but did not puzzle the students who, when scoring, referred successfully to the differences between Bohr's postulate and de Broglie quantification of the wave like characteristics. Examiners marked this question without reference to particular physicist or what individuals suggested. As a result many scored the first mark for suggesting that electrons have wave like properties. The rest of the answers then commonly restated the stem of the question about a well-defined radius.

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