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A-level
PHYSICS
Paper 3
Section B Astrophysics
Time allowed: The total time for
both sections of this paper is
Materials
For this paper you must have: 2 hours. You are advised to
• a pencil and a ruler spend approximately
• a scientific calculator
• a Data and Formulae Booklet
50 minutes on this section.
• a protractor.
For Examiner’s Use
Instructions
Question Mark
• Use black ink or black ball-point pen.
• Fill in the boxes at the top of this page. 1
• Answer all questions. 2
• You must answer the questions in the spaces provided. Do not write 3
outside the box around each page or on blank pages.
4
• If you need extra space for your answer(s), use the lined pages at the end of
this book. Write the question number against your answer(s). 5
• Do all rough work in this book. Cross through any work you do not want TOTAL
to be marked.
• Show all your working.
Information
• The marks for questions are shown in brackets.
• The maximum mark for this paper is 35.
• You are expected to use a scientific calculator where appropriate.
• A Data and Formulae Booklet is provided as a loose insert.
*JUN2174083ba01*
IB/M/Jun21/E8 7408/3BA
, 2
Do not write
outside the
Section B box
Answer all questions in this section.
0 1 Figure 1 shows the evolution of a star similar to the Sun on a Hertzsprung-Russell
(HR) diagram.
Figure 1
0 1 . 1 State the evolutionary stage of the star at each of the points W, X, Y and Z.
[3 marks]
W
X
Y
Z
Theta Carinae is a star with a radius five times that of the Sun. It has a surface
temperature of 31 000 K.
0 1 . 2 Annotate Figure 1 with a T to show the position of Theta Carinae.
[1 mark]
*02*
IB/M/Jun21/7408/3BA
, 3
Do not write
outside the
An astronomer suggests that an Earth-sized planet orbits Theta Carinae. box
0 1 . 3 Explain one difficulty with using the transit method to detect this planet.
[2 marks]
0 1 . 4 The astronomer suggests that the Earth-sized planet receives a similar amount of
power from Theta Carinae as the Earth does from the Sun.
The average power output of the Sun is 3.8 × 1026 W.
Determine the orbital radius of the Earth-sized planet orbiting Theta Carinae.
[5 marks]
orbital radius = m 11
Turn over ►
*03*
IB/M/Jun21/7408/3BA