2024HSCShort answer

Q24 (a)

2 marks

Question

An absorption spectrum resulting from the passage of visible light from a star’s surface through its hydrogen atmosphere is shown. Absorption lines are labelled W to Z in the diagram.
Determine the surface temperature of the star.

Try the question before revealing the answer.

Solution

Criteria	Marks
Determines the surface temperature of the star	2
Provides a relevant step	1

Sample answer: From the graph, the peak wavelength is 500 nm. Using Wien’s Law, $T = \frac{b}{\lambda_{\max}}$ .

T = \frac{2.898 \times 10^{-3}}{500 \times 10^{-9}} = 5796\ \mathrm{K}

Supplied marking guidance · human reviewed

Compare this with your working, not only your final sentence.

Syllabus alignment

Module 7 · The Nature of Light

Light: Quantum ModelAnalyse black-body radiation and Wien's law as evidence for a quantum model of light.

Spot a problem? Send feedback