DP Physics (last assessment 2024)

Question 19N.2.HL.TZ0.8b(ii)

Date	November 2019	Marks available	[Maximum mark: 1]	Reference code	19N.2.HL.TZ0.8b(ii)
Level	HL	Paper	2	Time zone	TZ0
Command term	Estimate	Question number	b(ii)	Adapted from	N/A

b(ii).

[Maximum mark: 1]

19N.2.HL.TZ0.8b(ii)

The Bohr model for hydrogen can be applied to the singly-ionized helium atom. In this model the radius $r$ , in m, of the orbit of the electron is given by $r = 2.7 \times 10^{- 11} \times n^{2}$ where $n$ is a positive integer.

(b(ii))

Estimate for $n = 3$ , the ratio $\frac{circumference of orbit}{de Broglie wavelength of electron}$ .

State your answer to one significant figure.

[1]

Markscheme

$\frac{2 π r}{λ} = « \frac{2 π \times 9 \times 2.7 \times 10^{- 11}}{5.1 \times 10^{- 10}} = 2.99 » ≅ 3$ ✔

NOTE: Allow ECF from (b)(i)

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Additional higher level (AHL)

Additional higher level (AHL) » Topic 12: Quantum and nuclear physics » 12.1 – The interaction of matter with radiation

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

Question 19N.2.HL.TZ0.8b(ii)

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