DP Physics (last assessment 2024)

Question 19N.3.SL.TZ0.b(iii)

Date	November 2019	Marks available	[Maximum mark: 2]	Reference code	19N.3.SL.TZ0.b(iii)
Level	SL	Paper	3	Time zone	TZ0
Command term	Calculate	Question number	b(iii)	Adapted from	N/A

b(iii).

[Maximum mark: 2]

19N.3.SL.TZ0.b(iii)

Eta Cassiopeiae A and B is a binary star system located in the constellation Cassiopeia.

The following data are available.

Apparent brightness of Eta Cassiopeiae A = 1.1 × 10^–9 Wm^–2
Apparent brightness of Eta Cassiopeiae B = 5.4 × 10^–11 Wm^–2
Luminosity of the Sun, $L_{⊙}$ = 3.8 × 10²⁶ W

The distance of the Eta Cassiopeiae system from the Earth is 1.8 × 10¹⁷m. Calculate, in terms of $L_{⊙}$ , the luminosity of Eta Cassiopeiae A.

[2]

Markscheme

«use of $L = 4 π d^{2} b$ »

$L = 4 π \times {(1.8 \times 10^{17})}^{2} \times 1.1 \times 10^{- 9} « = 4.48 \times 10^{26} W »$ ✔

$L = 1.2 L_{⊙}$ ✔

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Option D: Astrophysics

Option D: Astrophysics » Option D: Astrophysics (Core topics) » D.1 – Stellar quantities

Option D: Astrophysics » Option D: Astrophysics (Core topics)

Question 19N.3.SL.TZ0.b(iii)

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