2024_AQA A-Level Physics Paper 3 Section B Astrophysics (Merged Question Paper and Marking Scheme)

2024_AQA A-Level Physics Paper 3 Section B Astrophysics (Merged Question Paper and Marking Scheme) Monday 17 June 2024 Monday 17 June 2024 Materials For this paper you must have:  a pencil and a ruler  a scientific calculator  a Data and Formulae Booklet  a protractor. Instructions Morning Time allowed: The total time for both sections of this paper is 2 hours. You are advised to spend approximately 50 minutes on this section.  Use black ink or black ball-point pen.  Fill in the boxes at the top of this page.  Answer all questions.  You must answer the questions in the spaces provided. Do not write outside the box around each page or on blank pages.  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).  Do all rough work in this book. Cross through any work you do not want 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. For Examiner’s Use Question Mark 1 2 3 4 TOTAL 7408/3BA A-Level Physics: Paper 3 Section B – Astrophysics: Exam Preview Sections Section B of Paper 3 focuses on Astrophysics, exploring the key concepts of the universe, from stars and galaxies to cosmology. You'll be tested on your understanding of astrophysical theories, observational techniques, and the ability to apply physics concepts to astronomical phenomena. 1. Stellar Formation and Evolution:  Stellar Lifecycles: Understand the life stages of stars, from nebulae to main-sequence stars, red giants, white dwarfs, and supernovae. o Learn the difference between low- and high-mass star evolution. o Understand nuclear fusion processes and how they power stars. o For high-mass stars, understand the concept of supernovae, the formation of neutron stars and black holes.  Hertzsprung-Russell (H-R) Diagram: Be familiar with how the H-R diagram is used to classify stars by their luminosity and temperature, and understand how stars evolve across the diagram. 2. Black Holes:  Formation of Black Holes: Understand the concept of gravitational collapse and how it leads to the formation of a black hole when a massive star runs out of fuel.  Event Horizon: Know the properties of a black hole’s event horizon, where not even light can escape.  Singularity: Understand the concept of singularity, the point of infinite density at the center of a black hole.  Detection of Black Holes: Learn how black holes are detected indirectly through their effect on nearby matter, such as by observing X ray emissions from accretion disks. 3. The Big Bang Theory and Cosmology: 4. Dark Matter and Dark Energy: 5. Observational Techniques:  Telescopes: Be familiar with the different types of telescopes (optical, radio, infrared, X-ray, etc.), and how each detects different wavelengths of electromagnetic radiation to observe objects in space.  Parallax and Distance Measurement: Know how stellar parallax is used to measure the distance to nearby stars and how to calculate distances in space. 6. Key Concepts to Revise:  Stellar evolution: Review the stages in the life cycle of stars, from nebula to supernova or white dwarf, and the processes that occur at each stage.  Black holes: Be able to explain the properties and formation of black holes and how they can be detected.  Cosmology: Understand the evidence for the Big Bang, the expansion of the universe, and the concepts of dark matter and dark energy.  Telescopes and observation: Review the various methods used to study distant astronomical objects and the information that can be derived from these observations. IB/M/Jun24/E6 2 Do not write outside the IB/M/Jun24/7408/3BA Section B Answer all questions in this section. box 0 1 A student uses a refracting telescope in normal adjustment to make observations of Jupiter. The telescope has an angular magnification of 75 0 1 . 1 The eyepiece has a focal length of 22 mm. Determine the distance between the eyepiece and the objective lens. [2 marks] distance = m 0 1 . 2 When viewed through the telescope, the image of Jupiter subtends an angle of 1.7 × 10−2 rad. Calculate, in km, the distance between the Earth and Jupiter. mean radius of Jupiter = 7.0 × 104 km [2 marks] distance = km 3 Do not write outside the box IB/M/Jun24/7408/3BA 11 The student places a cap over one end of the telescope. The cap has a circular hole in its centre. Figure 1 shows the end of the telescope, the objective lens and the cap. Figure 1 0 1 . 3 State and explain the effect that the addition of the cap has on the chromatic aberration caused by the lens. [3 marks] 0 1 . 4 Explain two other effects that the addition of the cap has on the image of Jupiter. [4 marks] 1 2 4 Turn over ► Do not write outside the box IB/M/Jun24/7408/3BA 5 Do not write outside the box IB/M/Jun24/7408/3BA 0 2 The apparent change in position of a nearby star relative to distant stars is due to an effect known as parallax. Figure 2 shows how parallax arises. As the Earth moves from point P to point Q, an observer on the Earth sees the position of a nearby star S change in relation to distant stars. Figure 2 Angle A is the parallax angle. This angle can be used to determine the distance to a nearby star, provided that the relative motion between the star and the Sun is negligible between observations. 0 2 . 1 The distance from the Sun to S is 79 ly. The Earth takes 6 months to move from point P to point Q. Calculate, in degrees, angle A. [2 marks] A = ° 6 Do not write outside the box IB/M/Jun24/7408/3BA 0 2 . 2 Parallax is used to determine the distance to a different star. Observations of the star produce the following data: distance determined using parallax = 0.40 pc apparent magnitude = 13.5 absolute magnitude = 16.7 An astronomer suggests that the star moved significantly relative to the Sun between the two parallax observations. Discuss whether this suggestion is valid. [4 marks] Turn over ► 6 7 0 3 . 1 Figure 3 shows the variation of intensity with wavelength for a star. Figure 3 Show that Figure 3 is consistent with a black-body temperature of about 6.0 × 103 K. [2 marks] 0 3 . 2 The radius of the star is 9.6 × 106 m. Calculate the power output of the star. [2 marks] power output = W Do not write outside the box IB/M/Jun24/7408/3BA 8 Do not write outside the IB/M/Jun24/7408/3BA 3 7 . Which row gives the type and spectral class of the star? Tick () one box. [1 mark] box . The light from the star passes through an interstellar dust cloud before reaching Earth. The reduction in intensity when light passes through a dust cloud is assumed to be inversely proportional to the wavelength of the light. An astronomer on the Earth estimates the black-body temperature of the star. Discuss the effect that the dust cloud has on this estimate. [2 marks] Turn over ► Type of star Spectral class white dwarf F main sequence G red giant K main sequence F red giant G white dwarf K 4 3 0 3 0 9 Do not write outside the IB/M/Jun24/7408/3BA There are no questions printed on this page DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED box 1 0 Do not write outside the IB/M/Jun24/7408/3BA Turn over ► box 0 4 The Earth is in the galaxy known as the Milky Way. The Andromeda Galaxy is one of the closest galaxies to the Milky Way. 0 4 . 1 The Andromeda Galaxy approaches the Milky Way at a speed of 110 km s−1. The distance between the galaxies is 770 kpc. Discuss whether these data can be used to estimate an age for the Universe. [2 marks] 0 4 . 2 There is a supermassive black hole at the centre of the Andromeda Galaxy. The mass of this black hole is 1.60 × 108 solar masses. Calculate the radius of the event horizon of this black hole. State an appropriate unit for your answer. [3 marks] radius = unit = Question 4 continues on the next page 11 IB/M/Jun24/7408/3BA Do not write outside the box Do not write outside the box 0 4 . 3 Scientists predict that a quasar will be produced as the Milky Way and the Andromeda Galaxy merge. Explain what is meant by a quasar. Go on to suggest why a quasar may be produced as galaxies merge. In your answer you should:  describe the typical properties of a quasar  explain how observations of quasars provide evidence for these properties  suggest the process of quasar formation that is likely when two galaxies merge. [6 marks] 12 IB/M/Jun24/7408/3BA 11 Do not write outside the box END OF QUESTIONS 13 IB/M/Jun24/7408/3BA There are no questions printed on this page DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED Do not write outside the box 14 Question number Additional page, if required. Write the question numbers in the left-hand margin. IB/M/Jun24/7408/3BA Do not write outside the box 15 Question number Additional page, if required. Write the question numbers in the left-hand margin. IB/M/Jun24/7408/3BA Do not write outside the box 16 Question number Additional page, if required. Write the question numbers in the left-hand margin. IB/M/Jun24/7408/3BA Do not write outside the box 17 Do not write outside the IB/M/Jun24/7408/3BA There are no questions printed on this page DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED box Copyright information For confidentiality purposes, all acknowledgements of third-party copyright material are published in a separate booklet. This booklet is published after each live examination series and is available for free download from . Permission to reproduce all copyright material has been applied for. In some cases, efforts to contact copyright-holders may have been unsuccessful and AQA will be happy to rectify any omissions of acknowledgements. If you have any queries please contact the Copyright Team. Copyright © 2024 AQA and its licensors. All rights reserved. A-level PHYSICS 7408/3BA Paper 3 Section B Astrophysics Mark scheme June 2024 Version: 1.0 Final MARK SCHEME – A-LEVEL PHYSICS – 7408/3BA – JUNE 2024 Mark schemes are prepared by the Lead Assessment Writer and considered, together with the relevant questions, by a panel of subject teachers. This mark scheme includes any amendments made at the standardisation events which all associates participate in and is the scheme which was used by them in this examination. The standardisation process ensures that the mark scheme covers the students’ responses to questions and that every associate understands and applies it in the same correct way. As preparation for standardisation each associate analyses a number of students’ scripts. Alternative answers not already covered by the mark scheme are discussed and legislated for. If, after the standardisation process, associates encounter unusual answers which have not been raised they are required to refer these to the Lead Examiner. It must be stressed that a mark scheme is a working document, in many cases further developed and expanded on the basis of students’ reactions to a particular paper. Assumptions about future mark schemes on the basis of one year’s document should be avoided; whilst the guiding principles of assessment remain constant, details will change, depending on the content of a particular examination paper. No student should be disadvantaged on the basis of their gender identity and/or how they refer to the gender identity of others in their exam responses. A consistent use of ‘they/them’ as a singular and pronouns beyond ‘she/her’ or ‘he/him’ will be credited in exam responses in line with existing mark scheme criteria. Further copies of this mark scheme are available from Copyright information AQA retains the copyright on all its publications. However, registered schools/colleges for AQA are permitted to copy material from this booklet for their own internal use, with the following important exception: AQA cannot give permission to schools/colleges to photocopy any material that is acknowledged to a third party even for internal use within the centre. Copyright © 2024 AQA and its licensors. All rights reserved. 2 MARK SCHEME – A-LEVEL PHYSICS – 7408/3BA – JUNE 2024 Physics - Mark scheme instructions to examiners 1. General The mark scheme for each question shows:  the marks available for each part of the question  the total marks available for the question  the typical answer or answers which are expected  extra information to help the Examiner make his or her judgement and help to delineate what is acceptable or not worthy of credit or, in discursive answers, to give an overview of the area in which a mark or marks may be awarded. The extra information is aligned to the appropriate answer in the left-hand part of the mark scheme and should only be applied to that item in the mark scheme. At the beginning of a part of a question a reminder may be given, for example: where consequential marking needs to be considered in a calculation; or the answer may be on the diagram or at a different place on the script. In general the right-hand side of the mark scheme is there to provide those extra details which confuse the main part of the mark scheme yet may be helpful in ensuring that marking is straightforward and consistent. 2. Emboldening 2.1 In a list of acceptable answers where more than one mark is available ‘any two from’ is used, with the number of marks emboldened. Each of the following bullet points is a potential mark. 2.2 A bold and is used to indicate that both parts of the answer are required to award the mark. 2.3 Alternative answers acceptable for a mark are indicated by the use of or. Different terms in the mark scheme are shown by a / ; eg allow smooth / free movement. 3. Marking points 3.1 Marking of lists This applies to questions requiring a set number of responses, but for which candidates have provided extra responses. The general principle to be followed in such a situation is that ‘right + wrong = wrong’. Each error / contradiction negates each correct response. So, if the number of errors / contradictions equals or exceeds the number of marks available for the question, no marks can be awarded. However, responses considered to be neutral (often prefaced by ‘Ignore’ in the mark scheme) are not penalised. 3.2 Marking procedure for calculations Full marks can usually be given for a correct numerical answer without working shown unless the question states ‘Show your working’. However, if a correct numerical answer can be evaluated from incorrect physics then working will be required. The mark scheme will indicate both this and the credit (if any) that can be allowed for the incorrect approach. 3 MARK SCHEME – A-LEVEL PHYSICS – 7408/3BA – JUNE 2024 However, if the answer is incorrect, mark(s) can usually be gained by correct substitution / working and this is shown in the ‘extra information’ column or by each stage of a longer calculation. A calculation must be followed through to answer in decimal form. An answer in surd form is never acceptable for the final (evaluation) mark in a calculation and will therefore generally be denied one mark. 3.3 Interpretation of ‘it’ Answers using the word ‘it’ should be given credit only if it is clear that the ‘it’ refers to the correct subject. 3.4 Errors carried forward, consequential marking and arithmetic errors Allowances for errors carried forward are likely to be restricted to calculation questions and should be shown by the abbreviation ECF or conseq in the marking scheme. An arithmetic error should be penalised for one mark only unless otherwise amplified in the marking scheme. Arithmetic errors may arise from a slip in a calculation or from an incorrect transfer of a numerical value from data given in a question. 3.5 Phonetic spelling The phonetic spelling of correct scientific terminology should be credited (eg fizix) unless there is a possible confusion (eg defraction/refraction) with another technical term. 3.6 Brackets (…..) are used to indicate information which is not essential for the mark to be awarded but is included to help the examiner identify the sense of the answer required. 3.7 Ignore / Insufficient / Do not allow ‘Ignore’ or ‘insufficient’ is used when the information given is irrelevant to the question or not enough to gain the marking point. Any further correct amplification could gain the marking point. ‘Do not allow’ means that this is a wrong answer which, even if the correct answer is given, will still mean that the mark is not awarded. 3.8 Significant figure penalties Answers to questions in the practical sections (7407/2 – Section A and 7408/3A) should display an appropriate number of significant figures. For non-practical sections, an A-level paper may contain up to 2 marks (1 mark for AS) that are contingent on the candidate quoting the final answer in a calculation to a specified number of significant figures (sf). This will generally be assessed to be the number of sf of the datum with the least number of sf from which the answer is determined. The mark scheme will give the range of sf that are acceptable but this will normally be the sf of the datum (or this sf -1). An answer in surd form cannot gain the sf mark. An incorrect calculation following some working can gain the sf mark. For a question beginning with the command word ‘Show that…’, the answer should be quoted to one more sf than the sf quoted in the question