DP Physics (last assessment 2024)

Question 20N.3.SL.TZ0.17b(ii)

b(ii).

[Maximum mark: 3]

20N.3.SL.TZ0.17b(ii)

The data for the star Eta Aquilae A are given in the table.

$L_{⊙}$ is the luminosity of the Sun and $M_{⊙}$ is the mass of the Sun.

(b(ii))

Estimate, in $pc$ , the distance to Eta Aquilae A using the luminosity in the table, given that $L_{⊙} = 3.83 \times 10^{26} W$ .

[3]

Markscheme

Use of $d = \sqrt{\frac{L}{4 πb}}$ ✓

$= \sqrt{\frac{2630 \times 3.83 \times 10^{26}}{4 π \times 7.20 \times 10^{- 10}}}$ ✓

$« = \frac{1.055 \times 10^{19}}{3.26 \times 9.46 \times 10^{15}} » = 342 « pc »$ ✓

Award [3] marks for a bald correct answer between $340$ and $344 « pc »$

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