DP Physics (last assessment 2024)

Question 20N.3.HL.TZ0.a

[Maximum mark: 2]

20N.3.HL.TZ0.a

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.

Show by calculation that Eta Aquilae A is not on the main sequence.

[2]

Markscheme

$« \frac{L}{L_{⊙}} = \frac{M^{3.5}}{{M_{⊙}}^{3.5}} = 5 . 70^{3.5} = » 442$ ✓

the luminosity of Eta (2630 $L_{⊙}$ ) is very different «so it is not main sequence» ✓

Allow calculation of $L^{\frac{1}{3.5}}$ to give $M = 9.5$ $M_{⊙}$ so not main sequence

OWTTE

Examiners report

Most candidates were successful in using the mass luminosity relationship.

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