2024_AQA A-Level Physics Paper 3 Section A (Merged Question Paper and Marking Scheme) Monday 17 June 2024

2024_AQA A-Level Physics Paper 3 Section A (Merged Question Paper and Marking Scheme) Monday 17 June 2024 Please write clearly in block capitals. Centre number Surname Forename(s) Candidate signat ure Candidate number I declare this is my own work. A-level PHYSICS Paper 3 Section A 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 70 minutes on this section. For Examiner’s Use  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 45.  You are expected to use a scientific calculator where appropriate.  A Data and Formulae Booklet is provided as a loose insert. Question Mark 1 2 3 TOTAL IB/M/Jun24/G4005/E9 A-Level Physics: Paper 3 Section A: Exam Preview sections This paper focuses on practical applications and investigations related to the physics topics you have studied. Section A typically tests your ability to design experiments, analyze data, and apply theoretical knowledge in practical contexts. 1. Practical Skills and Investigations:  Experimental Design: You may be asked to design an experiment to investigate a specific physical principle (e.g., measuring the acceleration due to gravity, investigating Ohm's Law, or determining the Young's modulus of a material). o Key components to consider: variables (independent, dependent, controlled), methods, safety, and equipment.  Data Analysis: Be prepared to interpret experimental data. This could involve using graphical methods (e.g., plotting graphs, finding gradients, and interpreting intercepts) and mathematical methods (e.g., calculating uncertainty, error propagation, and using appropriate formulae).  Uncertainty and Error: You’ll need to calculate uncertainties in measurements, including absolute and percentage uncertainty, and explain how to minimize errors in experiments. Understand how to report uncertainties when presenting results.  Practical Applications: You could be asked about the practical use of physical principles in real-world situations (e.g., how materials with different elastic properties are used in engineering or how radioactivity is measured in a medical context). 2. Key Topics for Practical Investigation:  Mechanics: o Investigating motion using different methods (e.g., measuring velocity, acceleration, or forces in various setups). o Understanding force and momentum through experiments with colliding objects or measuring forces in systems like pulleys or springs.  Electricity: o Setting up circuits to investigate Ohm’s Law, the relationship between voltage, current, and resistance in components (resistors, thermistors, diodes, etc.). o Experimenting with Kirchhoff’s laws to analyze complex circuits.  Waves: o Investigating wave properties such as wavelength, frequency, and velocity using apparatus like a ripple tank or oscilloscopes. o Experiments to demonstrate interference and diffraction, especially for light and sound waves.  Materials: o Testing the elastic properties of materials, including how to determine the Young’s modulus of a material through stretching experiments. o Investigating the stress-strain relationship and applying it to real materials like rubber or metal wires. 7408/3A 2 Do not write outside the box Section A IB/M/Jun24/7408/3A Answer all questions in this section. 0 1 This question is based on a method to determine the resistivity of a wire (required practical activity 5). Figure 1 shows a micrometer screw gauge. Figure 1 Figure 2 shows an enlarged view of the scales. Figure 2 3 Do not write outside the box IB/M/Jun24/7408/3A 0 1 . 1 State, in mm, the resolution of the main scale. [1 mark] resolution = mm 0 1 . 2 What is the reading on the micrometer? Tick () one box. [1 mark] 6.22 mm 6.72 mm 6.78 mm 8.22 mm 0 1 . 3 A wire X is placed in the gap between the anvil and the spindle. State and explain how this gap is closed just before taking a reading of the diameter of X. [1 mark] Question 1 continues on the next page Turn over ► 4 Do not write outside the box IB/M/Jun24/7408/3A Figure 3 shows a circuit used to determine the resistance per metre of wire X. Figure 3 Two terminals are used to mount X on a ruler. Clips are used to connect a voltmeter across the 1.2 Ω resistor. When the switch is closed, the voltmeter reading is 931 mV. The switch is then opened and the voltmeter is connected to X as shown in Figure 4. Figure 4 5 Do not write outside the box IB/M/Jun24/7408/3A 0 1 . 4 When the switch is closed, the voltmeter reading is 397 mV. Show that, for the arrangement in Figure 4, the resistance R of the wire between the clips is about 0.5 Ω. [2 marks] Question 1 continues on the next page Turn over ► 6 The length of wire between the clips is L. Values of R are determined for different values of L. Figure 5 shows these data. Figure 5 0 1 . 5 Determine the resistance per metre of X. [2 marks] resistance per metre = Ω m−1 Do not write outside the box IB/M/Jun24/7408/3A 7 Do not write outside the IB/M/Jun24/7408/3A 6 . Table 1 shows the resistance per metre of various metal wires. The diameter of X is one of the values of d shown in Table 1. Table 1 box Resistance per metre of wire / Ω m−1 d / mm copper tungsten alumel nichrome 0.38 0.151 0.504 3.15 9.73 0.93 0.0247 0.0824 0.515 1.59 1.63 0.00805 0.0268 0.168 0.518 2.08 0.00494 0.0165 0.103 0.318 3.66 0.00160 0.00532 0.0333 0.103 Identify the metal used for X. Go on to determine the resistivity of the metal. State an appropriate SI unit for your answer. [4 marks] metal used for X = resistivity = SI unit = Question 1 continues on the next page Turn over ► 1 0 8 Do not write outside the box IB/M/Jun24/7408/3A 0 1 . 7 A student adds error bars for R and L to each point on Figure 5. She estimates that  each value of R has a percentage uncertainty of 6%  each value of L has an absolute uncertainty of 5 mm. Compare her error bars for the point at L = 209 mm with her error bars for the point at L = 388 mm. [2 marks] 9 Do not write outside the box IB/M/Jun24/7408/3A 15 0 1 . 8 Outline how error bars are used to determine the uncertainty in the gradient of a linear graph. [2 marks] Turn over for the next question Turn over ► 10 Do not write outside the box Figure 6 shows apparatus used to investigate how the resistance R of IB/M/Jun24/7408/3A a light-dependent resistor (LDR) varies with illumination. Figure 6 The ohm-meter  always displays a four-digit reading of R  can be set to the different ranges A to E shown in Table 2. Table 2 Setting Maximum reading displayed Minimum (non-zero) reading displayed Unit range A 199.9 000.1 Ω range B Ω range C 19.99 00.01 kΩ range D 199.9 000.1 kΩ range E 1.999 0.001 MΩ 0 2 11 Do not write outside the box IB/M/Jun24/7408/3A 0 2 . 1 Explain why the reading displayed in Figure 6 shows that the ohm-meter is set to range C. [1 mark] 0 2 . 2 The quantity EV is a measure of the intensity of the light incident on the LDR. The SI unit of EV is the lux (lx). The resistance R of the LDR is given by log(R / Ω) = −0.772 log(EV / lx) + 5.09 Show that EV for the arrangement shown in Figure 6 is about 130 lx. [2 marks] Question 2 continues on the next page Turn over ► 12 Do not write outside the box IB/M/Jun24/7408/3A R is recorded for different values of the vertical distance x between the lamp and the LDR. EV is calculated for each value of R. Figure 7 shows how EV varies with x. Figure 7 13 Do not write outside the box IB/M/Jun24/7408/3A It can be shown that E  1 V x2 0 2 . 3 Describe a method to show that Figure 7 confirms this relationship. You do not need to show any calculations. [2 marks] 0 2 . 4 Deduce the value of x when EV = 130 lx. [2 marks] x = mm Question 2 continues on the next page Turn over ► 14 Do not write outside the box IB/M/Jun24/7408/3A 0 2 . 5 R is measured when x = 450 mm. Figure 8 shows how the ohm-meter displays the values of R when set to range B and when set to range C. Figure 8 The uncertainty of the reading on the ohm-meter is ±2% of the displayed reading plus ±2 in the least significant digit. This means that:  using range B the maximum value of R is 1.02 × 1681 + 2 = 1717 Ω  using range C the minimum value of R is 0.98 × 1.68 – 0.02 = 1.63 kΩ. 15 Do not write outside the box Complete Table 3. IB/M/Jun24/7408/3A Go on to explain whether range B or range C should be used to measure R. [2 marks] Table 3 Setting Minimum R Maximum R range B Ω 1717 Ω range C 1.63 kΩ kΩ Question 2 continues on the next page Turn over ► 16 Do not write outside the box IB/M/Jun24/7408/3A Figure 9 shows the LDR being used to investigate the transmission of light through glass slides. Figure 9 The lamp and ohm-meter are switched on. R is recorded with different numbers of slides placed on the LDR. EV is calculated for each value of R. 0 2 . 6 The positions of the lamp and the LDR are not changed during the experiment. Identify two other control variables. [2 marks] 1 2 17 Do not write outside the box IB/M/Jun24/7408/3A 0 2 . 8 In an experiment μ = 9.0 × 10−2 Deduce the minimum number of slides needed to reduce EV by 50%. [2 marks] number of slides = 15 0 2 . 7 For the arrangement in Figure 9 it can be shown that EV = 400 e−μN where N is the number of slides μ is a constant. Explain how μ can be determined from a linear graph. [2 marks] Turn over ► 18 Do not write outside the box IB/M/Jun24/7408/3A 0 3 This question is about a method to investigate how the force on a conductor varies with flux density and current (required practical activity 10). Figure 10 shows a copper rod clamped above a horizontal bench. Figure 10 19 Do not write outside the box IB/M/Jun24/7408/3A 0 3 . 1 Describe a method to show that the copper rod is horizontal. Your method must include the use of a metre ruler. You may annotate Figure 10. [3 marks] Question 3 continues on the next page Turn over ► 20 Do not write outside the box IB/M/Jun24/7408/3A Figure 11 shows the copper rod positioned above a digital balance. Two identical magnets are mounted on a steel yoke with their opposite poles facing each other. The balance is zeroed. The yoke is then placed on the balance so that a horizontal uniform magnetic field is applied perpendicular to the copper rod. The ends of the rod are connected as shown. Figure 11 0 3 . 2 When the switch is open, the reading on the balance shows the mass of the yoke and the two magnets. When the switch is closed, the reading on the balance decreases. Explain, with reference to Figure 11, the direction of the horizontal magnetic field. [3 marks] 21 Do not write outside the box IB/M/Jun24/7408/3A The current I in the rod is varied. The balance reading M1 is recorded for different values of I. The switch is now opened. Two additional magnets, identical to those used before, are attached to the yoke. Figure 12 shows how this new arrangement compares with the arrangement in Figure 11. Figure 12 The balance reading with four magnets attached to the yoke is M2. With the switch open, M2 is the mass of the yoke and the four magnets. The switch is now closed. M2 is recorded for different values of I. Question 3 continues on the next page Turn over ► 22 Do not write outside the box IB/M/Jun24/7408/3A Figure 13 shows data from both experiments. Values of M1 and M2 are plotted using different vertical axes. Figure 13 23 Do not write outside the box IB/M/Jun24/7408/3A It can be shown that M = kBI + nZ + Y where M = balance reading when the current is I B = magnetic flux density of the horizontal uniform magnetic field n = number of magnets attached to the yoke Z = mass, in g, of each magnet Y = mass, in g, of the yoke k is a constant. 0 3 . 3 Deduce the fundamental base units for k. [3 marks] fundamental base units = 0 3 . 4 Determine Y. [3 marks] Y = g Question 3 continues on the next page Turn over ► 24 Do not write outside the box IB/M/Jun24/7408/3A 15 0 3 . 5 A student sets up the apparatus with the copper rod positioned incorrectly. Figure 14 shows how the student’s arrangement compares with the correct arrangement. Figure 14 The student produces a graph of M1 against I. Compare the student’s graph with the graph of M1 against I (the solid line) in Figure 13. Explain your answer. [3 marks] END OF QUESTIONS 25 Do not write outside the box There are no questions printed on this page IB/M/Jun24/7408/3A DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED 26 Additional page, if required. Write the question numbers in the left-hand margin. Question number IB/M/Jun24/7408/3A Do not write outside the box 27 Additional page, if required. Write the question numbers in the left-hand margin. Question number IB/M/Jun24/7408/3A Do not write outside the box 28 Do not write outside the box IB/M/Jun24/7408/3A Question number Additional page, if required. Write the question numbers in the left-hand margin. 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 7408/3A Paper 3 Section A Mark scheme June 2024 Version: 1.0 Final MARK SCHEME – A-LEVEL PHYSICS – 7408/3A – 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 – 7408/3A – 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 – 7408/3A – 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 eg ‘Show that X is equal to about 2.1 cm’ – 4 MARK SCHEME – A-LEVEL PHYSICS – 7408/3A – JUNE 2024 answer should be quoted to 3 sf. An answer to 1 sf will not normally be acceptable, unless the answer is an integer eg a number of objects. In non-practical sections, the need for a consideration will be indicated in the question by the use of ‘Give your answer to an appropriate number of significant figures’. 3.9 Unit penalties An A-level paper may contain up to 2 marks (1 mark for AS) that are contingent on the candidate quoting the correct unit for the answer to a calculation. The need for a unit to be quoted will be indicated in the question by the use of ‘State an appropriate SI unit for your answer’. Unit answers will be expected to appear in the most commonly agreed form for the calculation concerned; strings of fundamental (base) units would not. For example, 1 tesla and 1 Wb m–2 would both be acceptable units for magnetic flux density but 1 kg m2 s–2 A–1 would not. 3.10 Level of response marking instructions Level of response mark schemes are broken down into three levels, each of which has a descriptor. The descriptor for the level shows the average performance for the level. There are two marks in each level. Before you apply the mark scheme to a student’s answer read through the answer and annotate it (as instructed) to show the qualities that are being looked for. You can then apply the mark scheme. Determining a level Start at the lowest level of the mark scheme and use it as a ladder to see whether the answer meets the descriptor for that level. The descriptor for the level indicates the different qualities that might be seen in the student’s answer for that level. If it meets the lowest level then go to the next one and decide if it meets this level, and so on, until you have a match between the level descriptor and the answer. With practice and familiarity you will find that for better answers you