IB Physics SL B.1.17 Wien's Displacement Law

Practise reading peak wavelength from a black-body spectrum and applying Wien's law to find temperature or wavelength, with careful conversion between nanometres and metres.

Exam points

identify λmax at the spectrum peak rather than at the greatest wavelength shown
apply λmaxT = 2.9 × 10⁻³ m K and convert nanometres to metres before substitution
compare spectra by recognising that a hotter body has a shorter peak wavelength

[Maximum number: 1]

Star A is a main sequence star.

The data for Star A and the Sun are given in a table.

Table for Question B.1.17—Wien’s displacement law question 1 — IB Physics SL

Show that the peak wavelength emitted from Star A is about 560 nm .

$\lambda_{\text {max }}=\frac{2.9 \times 10^{-3}}{5200}=5.58 \times 10^{-7} \mathrm{~m}$ OR $558 \mathrm{~nm}$

Must see full substitution OR
answer to 3 (or more) significant
figures.

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B.1.17—Wien’s displacement law question 1