Aqa Gcse Physics Paper 2 Mark Scheme Latest Version

AQA GCSE PHYSICS PAPER 2 MARK SCHEME LATEST VERSION GCSE COMBINED SCIENCE: TRILOGY 8464/P/2H Physics Paper 2H Mark scheme June 2020 Version: 1.0 Final Mark Scheme *206G 464p2h/MS* 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. 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. 2 Copyright © 2020 AQA and its licensors. All rights reserved. Downloaded by: NewAcademicsSolutions | 3 Information 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 • the Assessment Objectives, level of demand and specification content that each question is intended to cover. 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 and underlining 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. 2.4 Any wording that is underlined is essential for the marking point to be awarded. 4 3. Marking points 3.1 Marking of lists This applies to questions requiring a set number of responses, but for which students 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 error / contradictions equals or exceeds the number of marks available for the question, no marks can be awarded. However, responses considered to be neutral (indicated as * in example 1) are not penalised. Example 1: What is the pH of an acidic solution? Student Response Marks awarded 1 green, 5 0 2 red*, 5 1 3 red*, 8 0 Example 2: Name two planets in the solar system. Student Response Marks awarded 1 Neptune, Mars, Moon 1 2 Neptune, Sun, Mars, Moon 0 3.2 Use of chemical symbols / formulae [1 mark] [2 marks] If a student writes a chemical symbol / formula instead of a required chemical name, full credit can be given if the symbol / formula is correct and if, in the context of the question, such action is appropriate. 3.3 Marking procedure for calculations Marks should be awarded for each stage of the calculation completed correctly, as students are instructed to show their working. Full marks can, however, be given for a correct numerical answer, without any working shown. 3.4 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. 5 3.5 Errors carried forward Any error in the answers to a structured question should be penalised once only. Papers should be constructed in such a way that the number of times errors can be carried forward is kept to a minimum. Allowances for errors carried forward are most likely to be restricted to calculation questions and should be shown by the abbreviation ecf in the marking scheme. 3.6 Phonetic spelling The phonetic spelling of correct scientific terminology should be credited unless there is a possible confusion with another technical term. 3.7 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. 3.8 Allow In the mark scheme additional information, ‘allow’ is used to indicate creditworthy alternative answers. 3.9 Ignore Ignore 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. 3.10 Do not accept Do not accept means that this is a wrong answer which, even if the correct answer is given as well, will still mean that the mark is not awarded. 4. Level of response marking instructions Extended response questions are marked on level of response mark schemes. • Level of response mark schemes are broken down into 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. Step 1: Determine a level Start at the lowest level of the mark scheme and use it as a ladder to see whether the 6 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. 7 When assigning a level you should look at the overall quality of the answer. Do not look to penalise 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. 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 but be awarded a mark near the top of the level because of the level 3 content. Step 2: Determine a mark Once you have assigned a level you need to decide on the mark. The descriptors on how to allocate marks can help with this. The exemplar materials used during standardisation will help. 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. Indicative content in the mark scheme is provided as a guide for examiners. It is not intended to be exhaustive and you must credit other valid points. Students do not have to cover all of the points mentioned in the indicative content to reach the highest level of the mark scheme. You should ignore any irrelevant points made. However, full marks can be awarded only if there are no incorrect statements that contradict a correct response. An answer which contains nothing of relevance to the question must be awarded no marks. 6 Question Answers Extra information Mark AO / Spec. Ref. 01.1 iron and steel will be attracted (to the magnet) 1 AO1 6.7.1. 1 aluminium, copper and tin will not be attracted (to the magnet) 1 allow 1 mark is one metal is in the incorrect list, but all the other four are correct if no other mark awarded allow 1 mark for iron and steel are magnetic 01.2 the paperclip would 1 AO1 still be attracted to the 6.7.1. magnet 1 because of induced magnetism allow the paper clip becomes an induced magnet 1 allow because the paper clip is a temporary magnet allow there is a magnetic field at the south pole 01.3 weight = mass × do not accept gravity 1 AO1 gravitational field for gravitational field 6.5.1. strength strength 3 or W = mg 01.4 1.0 g = 0.0010 kg allow 0.001 (kg) 1 AO2 6.5.1. 3 weight of 1 paperclip = 0.0010 × 9.8 allow 0.0098 (N) allow correct substitution using incorrectly/not converted value of mass of 1 7 paperclip Force = 0.0098 x 20 = 0.196 (N) allow correct calculation using incorrectly/not 1 converted value of mass of paperclip 8 Total 8 Question Answers Mark AO / Spec. Ref. 02.1 Level 3: The method would lead to the production of a valid outcome. All key steps are identified and logically sequenced. 5–6 AO3 AO1 AO1 6.5.4.2.2 RPA19 Level 2: The method would not necessarily lead to a valid outcome. Most steps are identified, but the plan is not fully logically sequenced. 3–4 Level 1: The method would not lead to a valid outcome. Some relevant steps are identified, but links are not made clear. 1–2 No relevant content 0 Indicative content measurements • place one wooden block under the ramp • vary the height by placing a different number of wooden blocks • measure the height of the ramp using a metre rule • measure the distance travelled using a metre rule • measure time taken using light gates (and computer/datalogger) • measure time taken using a stopclock or ticker timer • release trolley from the same position each time • release the trolley without applying a force results • repeat at the same height and calculate a mean • repeat for different heights 2- u2 • calculate acceleration using a = (v-u)/t or a = v 2s 9 Question Answers Extra information Mark AO / Spec. Ref. 02.2 all points plotted correctly allow 1 mark for 3 points 2 AO2 plotted correctly 6.5.4.2.2 RPA19 height of ramp in metres on x- both quantity and unit required 1 axis and acceleration in m/s2 for both axes on y-axis) correct line of best fit 1 02.3 resultant force = mass × acceleration or F = ma 1 AO1 6.5.4.2. 2 RPA19 02.4 0.63 = m × 2.1 1 AO2 6.5.4.2. m =0.63 2.1 1 2 RPA19 m = 0.30 (kg) allow 0.3 (kg) 1 Total 14 1 question Answers Extra information Mark AO / Spec. Ref. 03.1 the spring will return to its original length when the force is removed 1 AO1 6.5. 3 03.2 Any two from: • spring constant • (original) length • diameter 2 AO3 6.5. 3 03.3 0.80 = k × 0.0040 k 0.80 = 0.0040 k = 200 (N/m) 1 AO2 6.5.3 1 1 03.4 the upward force on the spring 1 AO3 is equal to the downward force 6.5.3 the spring is inelastically 1 deformed Total 8 1 Question Answers Extra information Mark AO / Spec. Ref. 04.1 (vector quantity) has magnitude 1 AO1 and a direction 6.5.4.1. 3 (scalar quantity) has 1 magnitude only 04.2 resistive force acts on the ball allow friction or air resistance 1 AO2 6.5.4.2. 1 so (resultant) force in opposite direction to velocity 1 or so work is done on the ball 04.3 momentum = mass × velocity or p = mv 1 AO2 6.5.5. 1 04.4 26 = m × 5.0 1 AO2 m = 26 5.0 1 6.5.5.1 5.2 (kg) 1 04.5 momentum is conserved in 1 AO1 the collision (assuming no 6.5.5. external forces) 2 momentum of the pin increases 1 therefore the momentum of the ball must decrease. 1 1 1 exerts an equal and opposite force on the ball Total 11 Question Answers Extra information Mark AO / Spec. Ref. 05.1 X-rays are absorbed by bone 1 AO1 6.6.2.4 but can pass through flesh ignore skin 1 05.2 taking lots of X-rays would 1 AO3 give a large dose 6.6.2. 3 which would increase 1 the radiographer’s risk the screen absorbs some of allow screen reduces 1 the X-rays the risk/dose received by the radiographer 05.3 electrical current / oscillations in the transmitter producing radio waves 1 AO1 6.6.2. 3 radio waves are absorbed by the receiver inducing electrical current / oscillations in the receiver 1 at the same frequency 1 if no other mark is awarded, allow 1 mark for radio waves transfer information/energy through the air Total 8 1 Question Answers Extra information Mark AO / Spec. Ref. 06.1 13.5 × 2 3 9.0 (m/s) OR 13.5 × 1 = 4.5 (1) 3 13.5 - 4.5 = 9.0 (m/s) (1) 1 AO2 6.5.4. 3 allow 9 (m/s) 1 06.2 reduced speed allow reduces thinking / 1 AO1 reduces stopping braking distance 6.5.4.3. distance 2 6.5.4.3.3 means less chance of 1 collision OR the car will have less kinetic energy (1) so less likely to cause injury in the event of a collision (1) 06.3 14 = v × 0.70 v = 14 0.70 v = 20 (m/s) 02–202 = 2 × (–6.25) × s 202 s = (2 × 6.25) s = 32 (m) 1 AO2 6.5.4.1. 2 1 6.5.4.1. 5 1 1 1 ignore minus signs throughout 1 1 06.4 same maximum force 1 AO2 applied by the brakes because mass is less there allow momentum for mass 1 is a greater deceleration AO1 braking distance is less 1 AO1 OR 6.5. 2 reducing the mass reduced the kinetic energy of the van (at a given speed) (1) less work needed to be done to bring the van to a stop (1) (force from the brakes is the same) so braking distance is less (1) Total 13 1 Question Answers Extra information Mark AO / Spec. Ref. 07.1 the downward force on allow when there is a 1 AO3 the balance increased current in the wire there is a 6.7.2. magnetic field around the 2 wire (which causes a 6.5.4.2. magnetic force) 3 therefore the wire 1 must experience an equal and opposite force (which is upwards) 07.2 calculate the difference between the two mass readings allow 254.8 – 252.3 = 2.5 1 AO1 6.7.2. 2 convert to kg and multiply by gravitational field strength allow (2.5 / 1000) × 9.8 = 0.02375 (N) 1 07.3 (0.0210 – 0.0) gradient = (0.70 – 0.02) gradient = 0.031 0.031 = B × 0.125 B = 0.25 T 1 AO3 allow answer correctly given to 1 AO3 any number of significant figures allow correct substitution using 1 AO2 correctly calculated value given to any number of significant figures allow answer correctly given to 1 AO2 any number of significant figures any rounding must be correct for 6.7.2.2 subsequent marks to be awarded. max 2 marks if a pair of readings from the graph are 1 used instead of gradient calculation Total 8 1