A-level
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PHYSICS
7408/2
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Paper 2
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Mark scheme
June 2024
Version: 1.0 Final
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, MARK SCHEME – A-LEVEL PHYSICS – 7408/2 – JUNE 2024
Physics - Mark scheme instructions to examiners
1. General
The mark scheme for each question shows:
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• 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
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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.
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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.
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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
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consistent.
2. Emboldening
2.1 In a list of acceptable answers where more than one mark is available ‘any two from’ is used,
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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
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mark scheme are shown by a / ; eg allow smooth / free movement.
3. Marking points
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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’.
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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.
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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.
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, 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’
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Answers using the word ‘it’ should be given credit only if it is clear that the ‘it’ refers to the correct
subject.
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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.
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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
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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
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(…..) 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.
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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
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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.
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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
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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’ –
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, 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
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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.
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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
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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
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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
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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
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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.
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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
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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.
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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.
An answer which contains nothing of relevance to the question must be awarded no marks.
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Question Answers Additional comments/Guidelines Mark AO
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01.1
n = 43.1 (≥ 2 SF) 105 × 103 × 1 1 AO1
n=
8.31× ( 273 + 20.0 )
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Question Answers Additional comments/Guidelines Mark AO
끫븘끫븘
01.2 Use of 끫뢴 = 끫뢶끫뢂 OR 끫뢴 = 끫븘끫븘 Allow ecf for incorrect 끫뢰 and/or 끫뢶 in 1.1 3 AO2
끫롨
끫뢴gas
OR use of 끫뢴molecule = OR 끫뢂 = 끫뢶끫뢂끫롨 Several approaches are possible
끫뢂끫롨
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3끫뢺 끫뢺끫븘 1.25×1.00
OR (끫뢠rms )2 = seen in any form 끫뢴 = = = 4.82 × 10−26
끫븘 끫뢶끫뢂끫롨 43.1×6.02×1023
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OR use of their mass with 끫뢺끫븘 = 끫뢂끫뢴(끫뢠rms )2 (5.1 × 10−26 if 40 used)
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1 3
OR use of 끫뢴(끫뢠rms )2 = 끫뢰끫뢰 1
2 2
3kT 3 ×1.38 ×10−23 × 293
Correct answer see table 2 =
crms = = 502
m 4.82 ×10−26
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OR
Correct SF see table 3
Nm 1
끫뤞 2
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pV = Nm(crms ) 2 p = Nm(crms ) 2
끫뤈rms / m s−끫뾞 SF 3 ρ 3
Without 끫뢶 500 − 503 3 SF (501 − 503)
끫뢶 more than 3SF 500 − 503 3 SF (501 − 503) 3 p 3끫뢺끫븘 3끫뢺×1
(crms )2 = �= = �
43.1 500 − 503 3 SF (501 − 503) ρ 끫뢂끫뢴 끫븘
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43 500 − 503 2 SF (500)
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482 − 484 3 ×105 ×103
(no evidence of =
2 or 1 SF (480 or 500) crms = 502
or 500 1.25
끫뢶 = 43 in 1.1)
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482 − 484
(evidence of 1 SF (500)
or 500
끫뢶 = 43 in 1.1)
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