2024_AQA A-Level Physics Paper 2 (Merged Question Paper and Marking Scheme) Thursday 6 June 2024

2024_AQA A-Level Physics Paper 2 (Merged Question Paper and Marking Scheme) Thursday 6 June 2024 Please write clearly in block capitals. Centre number Surname Forename(s) Candidate number Candidate signatu re A-level PHYSICS Paper 2 I declare this is my own work. Thursday 6 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  Use black ink or black ball-point pen.  Fill in the boxes at the top of this page.  Answer all questions. Morning  You must answer the questions in the spaces provided. Do not write outside the box around each page or on blank pages. Time allowed: 2 hours For Examiner’s Use Question Mark 1 2 3 4 5 6 7 8–32  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 85.  You are expected to use a scientific calculator where appropriate.  A Data and Formulae Booklet is provided as a loose insert. TOTAL A-Level Physics: Paper 2 Exam Preview sections This paper assesses your understanding of waves, electricity, radioactivity, and particle physics, which cover the deeper concepts beyond basic mechanics and electricity. It requires you to apply both theoretical knowledge and problem-solving skills in more advanced areas of physics. 1. Waves:  Wave Properties: Review the key characteristics of waves—wavelength, frequency, amplitude, and speed. Use the wave equation v=fλv = f lambdav=fλ to solve problems.  Transverse and Longitudinal Waves: Understand the difference between these two types of waves (e.g., light vs sound) and their behaviors.  Interference and Diffraction: o Interference patterns: How to explain and solve problems involving constructive and destructive interference, especially in experiments like Young’s double-slit experiment. o Diffraction: Understand how waves spread out when passing through narrow slits and the conditions required for significant diffraction to occur.  Standing Waves: Study the formation of standing waves in strings and air columns, and know how to identify nodes and antinodes. 2. Electricity:  Current and Voltage: Revisit the concept of electric current (I=QtI = frac{Q}{t}I=tQ) and voltage (V=IRV = IRV=IR) and their relationships in circuits.  Resistance and Resistivity: o Ohm’s Law: Apply Ohm's Law to solve problems involving resistance in various circuit configurations. o Resistivity: Understand how resistance is related to a material’s properties using R=ρLAR = rho frac{L}{A}R=ρAL and be able to solve problems that require this. 3. Radioactivity:  Radioactive Decay: Know the types of radiation (alpha, beta, gamma) and how they affect materials and are measured.  Half-Life: Understand and calculate the half-life of a substance, and how to use this concept in problems involving radioactive decay.  Nuclear Fission and Fusion: Know the basic principles behind nuclear fission (splitting of large nuclei) and nuclear fusion (joining small nuclei), including their applications, like in nuclear reactors and stars. 5. Key Areas to Revise:  Wave behavior: Be sure you can explain interference and diffraction, and how standing waves are formed in different scenarios.  Electricity: Focus on Ohm’s Law, calculating resistance in different circuits, and understanding the relationship between voltages, current, and power.  Radioactivity: Understand radioactive decay and be able to solve problems involving half-life and the different types of radiation.  Particle Physics: Be familiar with atomic structure, subatomic particles, and the Standard Model. This paper will test your understanding of advanced wave phenomena, electricity, radioactivity, and particle physics. A solid understanding of both theory and problem-solving will be key to doing well. Practice applying concepts to a variety of questions, especially those involving calculations and practical applications. Let me know if you'd like more details on any topic! 7408/2 IB/M/Jun24/E11 2 IB/M/Jun24/7408/2 Do not write outside the box Section A Answer all questions in this section. Do not write outside the box 0 1 A room contains dry air at a temperature of 20.0 °C and a pressure of 105 kPa. 0 1 . 1 Show that the amount of air in each cubic metre is about 40 mol. [1 mark] 0 1 . 2 The density of the dry air is 1.25 kg m−3. Calculate crms for the air molecules. Give your answer to an appropriate number of significant figures. [3 marks] crms = m s−1 0 1 . 3 Calculate, in K, the change of temperature that will double crms for the air molecules. [2 marks] change of temperature = K 3 IB/M/Jun24/7408/2 9 0 1 . 4 A room contains moist air at a temperature of 20 °C. A dehumidifier cools and then condenses water vapour from the moist air. The final temperature of the liquid water that collects in the dehumidifier is 10 °C. Drier air leaves the dehumidifier at a temperature of 20 °C. Table 1 compares the air flowing into and out from the dehumidifier. Table 1 mass of water mass of air moist air flowing in 0.0057 drier air flowing out 0.0037 In one hour, a volume of 960 m3 of air flows through the dehumidifier. Assume that the density of the air remains constant at 1.25 kg m−3. Determine how much heat energy is removed in one hour from the water vapour by the dehumidifier. specific heat capacity of water vapour = 1860 J kg−1 K−1 specific latent heat of vaporisation of water = 2.3 × 106 J kg−1 [3 marks] heat energy removed = J Turn over ► Do not write outside the box 4 IB/M/Jun24/7408/2 Do not write outside the box 0 2 Figure 1 shows a circuit used to charge capacitor C. The battery has negligible internal resistance. Figure 1 The capacitance of C is known. 0 2 . 1 The switch is closed at time t = 0 and the potential difference VC across C is recorded at different times t. Figure 2 shows the variation of VC with t. Figure 2 Explain how a gradient of the graph in Figure 2 can be used to determine the initial current I0 in the circuit. [2 marks] 5 0 2 . 2 The potential difference VR across R is also recorded. Figure 3 shows the variation of VR with t between t = 20 s and t = 45 s. Figure 3 The capacitance of C is 31.0 μF. Determine, using Figure 3, the time constant of the circuit. Go on to show that the resistance of R is about 2.4 × 105 Ω. time constant = [2 marks] s resistance = Question 2 continues on the next page Ω Turn over ► Do not write outside the box IB/M/Jun24/7408/2 6 IB/M/Jun24/7408/2 Do not write outside the box 0 2 . 3 The current I0 at time t = 0 is 3.6 × 10−5 A. Determine the time at which VC is 6.0 V. [3 marks] time = s 0 2 . 4 Figure 4 shows two fully charged parallel-plate capacitors C1 and C2 in a circuit. A dielectric fills the space between the plates of C1 and air fills the space between the plates of C2. Figure 4 7 IB/M/Jun24/7408/2 Table 2 gives information about C1 and C2. Table 2 Do not write outside the box C1 C2 charge Q Q surface area S S potential difference V1 V2 plate separation d 2d dielectric constant 4.0 1.0 Determine V1 . V2 [2 marks] V1 = V2 Turn over for the next question Turn over ► 9 8 IB/M/Jun24/7408/2 Do not write outside the box 0 3 A conducting rod is held horizontally in an east–west direction. The magnetic flux density of the Earth’s magnetic field is 4.9 × 10−5 T and is directed at an angle of 68° to the ground. 0 3 . 1 Figure 5 shows the arrangement. The rod has a length of 2.0 m. Figure 5 The rod is released and falls 8.0 m to the ground. It remains in a horizontal east–west direction as it falls. Determine the average emf across the rod during its fall to the ground. Assume that air resistance is negligible. [3 marks] average emf = V 9 IB/M/Jun24/7408/2 7 0 3 . 2 The rod is returned to its original position. It is now supported by a non-conducting pole that is hinged on the ground as shown in Figure 6. The pole is initially vertical and is then released. The rod and pole can fall to the ground to the left or to the right. Figure 6 During each fall there are changes in the magnitude and direction of the induced emf. These changes differ depending on whether the rod falls to the left or to the right. Explain any changes in the magnitude and direction of the induced emf as the rod falls:  to the left  to the right. [4 marks] left right Turn over ► Do not write outside the box 10 IB/M/Jun24/7408/2 5 Do not write outside the box 0 4 . 1 One purpose of the coolant in a thermal nuclear reactor is to maintain a safe working temperature within the core. State the other purpose. [1 mark] 0 4 . 2 State two properties that engineers consider when choosing a liquid to use as a coolant in a thermal nuclear reactor. [2 marks] 1 2 0 4 . 3 Explain how the power output of a thermal nuclear reactor is decreased. [2 marks] 11 IB/M/Jun24/7408/2 Turn over for the next question DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED Do not write outside the box Turn over ► 12 IB/M/Jun24/7408/2 Do not write outside the box 0 5 A satellite S1 is placed in a circular orbit around the Earth so that observations of the far side of the Moon can be made continuously. S1 has the same angular speed as the Moon so that the centres of the Earth, the Moon and S1 are always in a straight line. Figure 7 shows two positions of the Moon and S1 as they orbit the Earth. Figure 7 13 IB/M/Jun24/7408/2 0 5 . 1 The resultant force on S1 is due to the gravitational forces from the Earth and the Moon. The magnitude of the Earth’s gravitational field strength at the orbital radius of S1 is 1.98 × 10−3 N kg−1. The magnitude of the Moon’s gravitational field strength at the orbital radius of S1 is gM. Show that gM is approximately 1.2 × 10−3 N kg−1. period of the Moon’s orbit = 27.3 days orbital radius of S1 = 4.489 × 105 km [3 marks] 0 5 . 2 Calculate the distance from S1 to the centre of the Moon. mass of the Moon = 7.35 × 1022 kg [2 marks] distance = m Question 5 continues on the next page Turn over ► Do not write outside the box 14 IB/M/Jun24/7408/2 Do not write outside the box 8 0 5 . 3 Another satellite S2 is placed in a circular orbit between the Earth and the Moon. S2 always views the near side of the Moon. S2 also has the same angular speed as the Moon so that the centres of the Earth, the Moon and S2 are always in a straight line. Figure 8 shows two positions of the Moon and S2 as they orbit the Earth. Figure 8 Explain how the resultant force on S2 due to the gravitational fields of the Earth and the Moon causes S2 to orbit with the same angular speed as the Moon. No calculations are required. [3 marks] 15 IB/M/Jun24/7408/2 Question 6 continues on the next page Do not write outside the box Turn over ► 0 6 . 1 The electric potential at a point in an electric field is −4.0 V. Explain what is meant by this statement. [3 marks] 16 Figure 9 shows an arrangement for confining groups of electrons to small regions inside a block of gallium arsenide. Figure 9 Electrons can only move along the line PQ in the block. When a suitable electric potential is applied to the electrodes, the electrons are confined to the regions shown in Figure 9. The graph in Figure 9 shows how the electric potential V varies with distance x along PQ. IB/M/Jun24/7408/2 Do not write outside the box 17 IB/M/Jun24/7408/2 Question 6 continues on the next page Turn over ► Do not write outside the box 0 6 . 2 Determine, using the graph in Figure 9, the maximum magnitude of the electric field. State an appropriate unit for your answer. [4 marks] maximum magnitude = unit 0 6 . 3 An electron at rest at x = 300 nm gains kinetic energy and moves to x = 800 nm. Determine the minimum kinetic energy required by the electron. [2 marks] minimum kinetic energy = J 18 IB/M/Jun24/7408/2 12 Do not write outside the box 0 6 . 4 One of the confined electrons is at x = 350 nm. Discuss the subsequent motion of this electron due to the variation in electric potential shown in Figure 9. Assume that the electron starts from rest. [3 marks] 19 IB/M/Jun24/7408/2 Question 7 continues on the next page Do not write outside the box Turn over ► 0 7 A team of students uses 900 dice, each with n sides, to model the decay of a radioactive material. Each dice represents a single undecayed nucleus. A throw of the dice represents a constant time interval. When the dice are thrown, those that show a 1 represent decayed nuclei and are removed. The students count the number N of ‘undecayed’ dice that remain. The procedure is repeated using the undecayed dice. Figure 10 shows the students’ data. Figure 10 0 7 . 1 Explain why N has been plotted on a logarithmic scale in Figure 10. [1 mark] 20 IB/M/Jun24/7408/2 Do not write outside the box 0 7 . 2 In this experiment, a decay constant λ can be defined that models the radioactive decay constant. Determine λ. Go on to use your value for λ to show that n = 4 for the dice used in this experiment. [5 marks] λ = throw−1 0 7 . 3 A typical radioactive source used in schools has an activity of 100 kBq. A radioactive source used in a hospital has an activity of 370 GBq. State one safety measure when using a radioactive source in a school laboratory. Go on to discuss how this safety measure needs to be adapted for safe use of the hospital radioactive source. [2 marks] 21 IB/M/Jun24/7408/2 10 END OF SECTION A Do not write outside the box Turn over ► 0 7 . 4 X-rays are a form of ionising radiation. A person has check-ups with a dentist every six months. The dentist only takes X-ray images when the person has reported a problem. Suggest why. [2 marks] 22 IB/M/Jun24/7408/2 Section B Each of Questions 08 to 32 is followed by four responses, A, B, C and D. For each question select the best response. Do not write outside the box Only one answer per question is allowed. For each question, completely fill in the circle alongside the appropriate answer. CORRECT METHOD WRONG METHODS If you want to change your answer you must cross out your original answer as shown. If you wish to return to an answer previously crossed out, ring the answer you now wish to select as shown. You may do your working in the blank space around each question but this will not be marked. Do not use additional sheets for this working. 0 8 In which process is work done by an ideal gas? [1 mark] A doubling the pressure at constant volume B doubling the volume at constant pressure C doubling the absolute temperature at constant volume D doubling the pressure at constant temperature 23 IB/M/Jun24/7408/2 0 9 Three molecules have speeds 2.00v, 4.00v and 5.00v. What is the crms speed of these molecules? [1 mark] A 3.50v B 3.67v C 3.87v D 26.0v 1 0 An ideal gas is enclosed in an insulated container with a small electric heater. The initial temperature of the gas is 300 K. The product of pressure and volume is 5000 J. The gas expands at constant pressure and does 1660 J of work. What is the final temperature of the gas? [1 mark] A 300 K B 400 K C 450 K D 900 K 1 1 An air-filled parallel-plate capacitor and a resistor are connected in series across the terminals of a battery. The plates of the capacitor are then moved further apart. This change results in [1 mark] A a decrease in the potential difference across the capacitor plates. B a decrease in the charge held on the capacitor plates. C an increase in the energy stored on the capacitor. D an increase in the capacitance of the capacitor. Turn over ► Do not write outside the box 24 IB/M/Jun24/7408/2 Do not write outside the box 1 2 Which change will increase the efficiency of a transformer? [1 mark] A increasing the thickness of the iron layers in the laminated core B decreasing the frequency of the ac input voltage C decreasing the diameter of the copper wire in the primary coil D increasing the distance between the primary coil and the secondary coil 1 3 A signal generator supplies a sinusoidal root mean square voltage of 7.0 V. The sinusoidal voltage is displayed on an oscilloscope screen. The screen has eight vertical divisions. Which volts/division setting will display the tallest complete waveform? [1 mark] A 1.5 V div−1 B 2.0 V div−1 C 2.5 V div−1 D 3.0 V div−1 25 IB/M/Jun24/7408/2 1 4 Two signals that have the same frequency are displayed simultaneously on an oscilloscope. The display is shown with the time-base set to 5 ms div−1. Which row shows the frequency of both signals and the phase difference between them? [1 mark] Frequency of both signals / Hz Phase difference / rad A 50 0.30π B 50 0.15π C 25 0.30π D 25 0.15π Turn over ► Do not write outside the box 26 IB/M/Jun24/7408/2 D C v r Do not write outside the box 2r B v Be 2me 1 5 A transmission cable consists of many strands of wire. Electrical energy is transmitted along the cable at a frequency of 50 Hz. Which change gives the largest increase in the efficiency of the electrical energy transfer along the cable? [1 mark] A doubling the transmission voltage of the cable B doubling the current in the cable C halving the resistivity of the material of the wires D halving the number of wires in the cable 1 6 An electron enters a uniform magnetic field at right angles to the field. The flux density of the field is B. The electron moves with a non-relativistic speed v in a circular path of radius r. What is the number of circuits completed by the electron in one second? [1 mark] A 2me Be 27 IB/M/Jun24/7408/2 B The mass of 235 U is greater than the sum of the masses of 87 Br and 146 La . 92 35 57 C The binding energy of the neutrons released in the reaction is zero. D The binding energy of 235 U is greater than the binding energy of 146 La . 92 57 1 7 The following reaction occurs when a proton and a carbon-13 13 C  nucleus fuse. 6 13 C + 1p  14 N 6 1 7 mass of 13 C nucleus = 13.00007 u 6 mass of 14 N nucleus = 13.99925 u 7 mass of proton = 1.00728 u What is the quantity of energy released? [1 mark] A 0.5 MeV B 1.1 MeV C 7.5 MeV D 8.8 MeV 1 8 The equation represents a typical fission reaction. 235 U + 1 n  87 Br  146 La  31 n Which statement about this reaction is not true? [1 mark] A 146 La has the greatest binding energy per nucleon of the three nuclides. 57 Turn over ► Do not write outside the box 28 IB/M/Jun24/7408/2 B  y 3 r  x    C 1 r  x 3  y    D 1 r  y 3  x    Do not write outside the box 1 9 5.6 kW h of heat energy is released when 1.0 kg of wood pellets are burnt in a power station. What is the mass lost in burning 1.0 kg of wood pellets? [1 mark] A 0 B 3.7 × 10−12 kg C 2.2 × 10−10 kg D 6.7 × 10−2 kg 2 0 The nuclear radius of an element with nucleon number x is r. What is the nuclear radius of an element with nucleon number y? [1 mark] A  x 3 r  y    29 IB/M/Jun24/7408/2 B R 3 16 C R 2 Turn over for the next question Do not write outside the box Turn over ► 2 1 A synchronous orbit of the Earth has a radius R. A planet has a mass twice the mass of the Earth. A day on the planet is one quarter of an Earth day. What is the radius of a synchronous orbit for this planet? [1 mark] A R 3 2 D 2R 8 2 2 An asteroid has a mass of 2 × 1017 kg and an escape velocity of 40 m s−1. What is the order of magnitude of the radius of the asteroid? [1 mark] A 103 m B 104 m C 105 m D 106 m 30 IB/M/Jun24/7408/2 B the charge stored on a capacitor consisting of two parallel plates of area 1 m2 separated by 1 m when the potential difference between the plates is 1 V C the work done when moving a 2 C charge from infinity to a distance of π m from the centre of a metal sphere that carries 2 C of charge D the charge on a metal sphere which experiences a force of 1 N when its centre is placed 1 m from the centre of a metal sphere that carries 1 C of charge Do not write outside the box 2 3 The diagram shows the gravitational field for a binary star system consisting of two stars X and Y of equal mass. Equipotential lines are shown as solid lines. Gravitational field lines are shown as dashed lines. Which statement is correct? [1 mark] A More work is done moving from Q to S to R than moving directly from Q to R. B No work is done moving from Q to R. C The gravitational field strength is the same at R and S. D The work done moving from Q to R and moving from Q to S is the same. 2 4 Which is equal to ε0? [1 mark] A the relative permittivity of a vacuum 31 IB/M/Jun24/7408/2 Turn over for the next question Do not write outside the box Turn over ► 2 5 The force between two point charges is F. The magnitude of each charge is doubled and the distance between them is halved. What is the new force between the two charges? [1 mark] A 16F B 8F C 2F D F 32 IB/M/Jun24/7408/2 Do not write outside the box A B C D A B C D 2 6 Which diagram shows a distribution of charge where the electric potential at P and the electric field at P are both zero? [1 mark] 33 IB/M/Jun24/7408/2 2 7 An ion has a specific charge of −7.1 × 107 C kg−1. It is held stationary in a vertical electric field on the surface of the Earth. What are the magnitude and direction of the electric field? [1 mark] A 1.38 × 10−7 V m−1 upwards B 1.38 × 10−7 V m−1 downwards C 7.24 × 106 V m−1 upwards D 7.24 × 106 V m−1 downwards 2 8 Which particle pair has the largest magnitude of electrostatic force when separated by gravitational force the same distance? [1 mark] A an electron and a positive pion B a helium nucleus and a proton C a proton and a positive pion D a proton and an electron 2 9 What can be deduced about the radius r of a nucleus of gold from the scattering of alpha particles by gold nuclei? [1 mark] A r < 10−14 m B r < 10−15 m C r ≈ 10−15 m D r ≈ 10−16 m Turn over ► Do not write outside the box 34 IB/M/Jun24/7408/2 Do not write outside the box 3 0 The graph shows a plot of neutron number N against proton number Z for the known atomic nuclei. The nuclide 115 Rh is likely to decay by 45 [1 mark] A α emission. B β+ emission. C β− emission. D electron capture. 35 IB/M/Jun24/7408/2 25 END OF QUESTIONS Do not write outside the box 3 1 Uranium-238 absorbs a neutron in the first stage in a series of nuclear reactions that end in a nucleus Z. 238 U + n  X 92 X  Y +  + v e Y  Z +  + v e How many neutrons does Z have? [1 mark] A 144 B 145 C 149 D 237 3 2 A rock sample is found to contain the stable isotope lead-207. When it was formed, the rock contained uranium-235 but did not contain any lead-207. Uranium-235 decays by a series of steps into lead-207. The half-life of uranium-235 is 0.71 billion years. The half-lives of the nuclides in the intermediate steps are negligible. The sample of rock now contains one atom of lead-207 for every four atoms of uranium-235. How long ago was the rock formed? [1 mark] A 0.23 billion years B 0.31 billion years C 1.4 billion years D 2.0 billion years 36 IB/M/Jun24/7408/2 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 37 Question number Additional page, if required. Write the question numbers in the left-hand margin. IB/M/Jun24/7408/2 Do not write outside the box 38 Question number Additional page, if required. Write the question numbers in the left-hand margin. IB/M/Jun24/7408/2 Do not write outside the box 39 Question number Additional page, if required. Write the question numbers in the left-hand margin. IB/M/Jun24/7408/2 Do not write outside the box 40 Do not write outside the IB/M/Jun24/7408/2 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 7408/2 Paper 2 Mark scheme June 2024 Version: 1.0 Final MARK SCHEME – A-LEVEL PHYSICS – 7408/2 – 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 – 7408/2 – 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 2.2 2.3 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. A bold and is used to indicate that both parts of the answer are required to award the mark. 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 – 7408/2 – 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 – 7408/2 – 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 will be able to quickly skip through the lower levels of the mark scheme. When assigning a level you should look at the overall quality of the answer and not look to pick holes in small and specific parts of the answer where the student has not performed quite as well as the rest. If the answer covers different aspects of different levels of the mark scheme you should use a best fit approach for defining the level and then use the variability of the response to help decide the mark within the level. ie if the response is predominantly level 2 with a small amount of level 3 material it would be placed in level 2. The exemplar materials used during standardisation will help you to determine the appropriate level. There will be an answer in the standardising materials which will correspond with each level of the mark scheme. This answer will have been awarded a mark by the Lead Examiner. You can compare the student’s answer with the example to determine if it is the same standard, better or worse than the example. You can then use this to allocate a mark for the answer based on the Lead Examiner’s mark on the example. You may well need to read back through the answer as you apply the mark scheme to clarify points and assure yourself that the level and the mark are appropriate.