Cambridge International AS & A Level

PHYSICS 9702/33
Paper 3 Advanced Practical Skills 1 May/June 2024
MARK SCHEME
Maximum Mark: 40

Published

This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.

Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.

Cambridge International will not enter into discussions about these mark schemes.

Cambridge International is publishing the mark schemes for the May/June 2024 series for most
Cambridge IGCSE, Cambridge International A and AS Level and Cambridge Pre-U components, and some
Cambridge O Level components.

This document consists of 9 printed pages.

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9702/33 Cambridge International AS & A Level – Mark Scheme May/June 2024
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Generic Marking Principles

These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alongside the
specific content of the mark scheme or generic level descriptions for a question. Each question paper and mark scheme will also comply with these
marking principles.

GENERIC MARKING PRINCIPLE 1:

Marks must be awarded in line with:

 the specific content of the mark scheme or the generic level descriptors for the question
 the specific skills defined in the mark scheme or in the generic level descriptors for the question
 the standard of response required by a candidate as exemplified by the standardisation scripts.

GENERIC MARKING PRINCIPLE 2:

Marks awarded are always whole marks (not half marks, or other fractions).

GENERIC MARKING PRINCIPLE 3:

Marks must be awarded positively:

 marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is given for valid answers which go beyond
the scope of the syllabus and mark scheme, referring to your Team Leader as appropriate
 marks are awarded when candidates clearly demonstrate what they know and can do
 marks are not deducted for errors
 marks are not deducted for omissions
 answers should only be judged on the quality of spelling, punctuation and grammar when these features are specifically assessed by the
question as indicated by the mark scheme. The meaning, however, should be unambiguous.

GENERIC MARKING PRINCIPLE 4:

Rules must be applied consistently, e.g. in situations where candidates have not followed instructions or in the application of generic level
descriptors.

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GENERIC MARKING PRINCIPLE 5:

Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range may
be limited according to the quality of the candidate responses seen).

GENERIC MARKING PRINCIPLE 6:

Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should not be awarded with grade thresholds or
grade descriptors in mind.

Science-Specific Marking Principles

1 Examiners should consider the context and scientific use of any keywords when awarding marks. Although keywords may be present, marks
should not be awarded if the keywords are used incorrectly.

2 The examiner should not choose between contradictory statements given in the same question part, and credit should not be awarded for
any correct statement that is contradicted within the same question part. Wrong science that is irrelevant to the question should be ignored.

3 Although spellings do not have to be correct, spellings of syllabus terms must allow for clear and unambiguous separation from other
syllabus terms with which they may be confused (e.g. ethane / ethene, glucagon / glycogen, refraction / reflection).

4 The error carried forward (ecf) principle should be applied, where appropriate. If an incorrect answer is subsequently used in a scientifically
correct way, the candidate should be awarded these subsequent marking points. Further guidance will be included in the mark scheme
where necessary and any exceptions to this general principle will be noted.

5 ‘List rule’ guidance

For questions that require n responses (e.g. State two reasons …):

 The response should be read as continuous prose, even when numbered answer spaces are provided.
 Any response marked ignore in the mark scheme should not count towards n.
 Incorrect responses should not be awarded credit but will still count towards n.
 Read the entire response to check for any responses that contradict those that would otherwise be credited. Credit should not be
awarded for any responses that are contradicted within the rest of the response. Where two responses contradict one another, this
should be treated as a single incorrect response.
 Non-contradictory responses after the first n responses may be ignored even if they include incorrect science.

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6 Calculation specific guidance

Correct answers to calculations should be given full credit even if there is no working or incorrect working, unless the question states ‘show
your working’.

For questions in which the number of significant figures required is not stated, credit should be awarded for correct answers when rounded
by the examiner to the number of significant figures given in the mark scheme. This may not apply to measured values.

For answers given in standard form (e.g. a  10n) in which the convention of restricting the value of the coefficient (a) to a value between 1
and 10 is not followed, credit may still be awarded if the answer can be converted to the answer given in the mark scheme.

Unless a separate mark is given for a unit, a missing or incorrect unit will normally mean that the final calculation mark is not awarded.
Exceptions to this general principle will be noted in the mark scheme.

7 Guidance for chemical equations

Multiples / fractions of coefficients used in chemical equations are acceptable unless stated otherwise in the mark scheme.

State symbols given in an equation should be ignored unless asked for in the question or stated otherwise in the mark scheme.

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Question Answer Marks

1(a) Value of a in range 46.0–49.0 cm with unit. 1

1(b) Value(s) of raw y to the nearest mm with unit. 1

1(c) Six sets of readings of n (different values, not including zero) and y with correct trend (y decreases as n increases) and 5
without help from the Supervisor scores 5 marks, five sets scores 4 marks etc.

Range: Includes n = 1 and n = 7. 1

Column headings: 1
Each column heading must contain a quantity and a unit where appropriate.
The presentation of quantity and unit must conform to accepted scientific convention e.g. y / cm and no units for n or 1 / n.

Significant figures: All values of y / n must be given to 3 s.f. 1

Calculation: Correct calculation of y / n. 1

1(d)(i) Axes: 1
Axes must be labelled with the required quantities.
Scales must be chosen so that the plotted points occupy at least half the graph grid in both x and y directions.
Scale markings are no more than 2 cm (one large square) apart.
Sensible scales must be used. Scales must not be awkward (e.g. 3:10 or fractions).

Plotting of points: 1
All observations in the table must be plotted on the grid.
Diameter of plotted points must be ⩽ half a small square.
Points must be plotted to an accuracy of half a small square in both the x and y directions.

Quality: 1
All points in the table (at least 5) must be plotted on the grid.
Trend must be correct.
It must be possible to draw a straight line that is within  0.04 on the 1 / n axis of all plotted points.

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Question Answer Marks

1(d)(ii) Line of best fit: 1

‘Best fit’ is judged by balance of all points on the grid (at least 5 points) about the candidate’s line.
There must be an even distribution of points either side of the line along the full length.
Line must not be kinked or thicker than half a small square.

Some candidates may choose to identify an anomalous point. If they identify one point as anomalous (e.g. by circling or
labelling) then this point is to be disregarded when judging the line of best fit. There must be at least 5 points left after the
anomalous point is disregarded.

1(d)(iii) Gradient: 1
The hypotenuse of the triangle used should be greater than half the length of the drawn line.
Both read-offs must be accurate to half a small square in both the x and y directions.
The method of calculation must be correct, not x / y.
The gradient sign on the answer line must be consistent with the graph drawn.

y-intercept: 1
Correct read-off from a point on the line and substituted correctly into y = mx + c or an equivalent expression.
Read-off accurate to half a small square in both the x and y directions.
or
Intercept read directly from the graph, with read-off at 1 / n = 0, accurate to half a small square in y direction.

1(e) Value of P = candidate’s gradient and value of Q = – candidate’s intercept. 1

The values must not be written as fractions or given to only one significant figure.

Units for P and Q: m, cm or mm consistent with y values given. 1

1(f) Correct calculation of R. 1

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Question Answer Marks

2(a)(i) Value(s) of raw L0 to the nearest mm with unit. 1

2(a)(ii) Percentage uncertainty in L0 based on absolute uncertainty in the range 2–10 mm. 1
Correct method of calculation to obtain percentage uncertainty e.g. (absolute uncertainty / value from (a)(i))  100.
If several readings have been taken, then the absolute uncertainty can be half the range (but not zero) provided the working
is shown clearly.

2(b) Values of w0 and t and w0  t. 1

All raw values of w0 and t to the same precision, either all to 0.01 mm or all to 0.001 mm with a unit. 1

2(c)(i) Values of L and w and L  L0. 1

2(c)(ii) Correct calculation of L and w. 1

2(c)(iii) Justification for significant figures in L linked to significant figures of (L – L0) (when calculated to the correct number of 1
decimal places).

2(d) Second values of L and w. 1

Second value of w  first value of w. 1

2(e) Two values of k calculated correctly. 1

The final k values must not be written as fractions or given to only one significant figure.

2(f) Calculation of percentage difference between candidate’s two k values. 1

Comparison of percentage difference with 25% leading to a consistent conclusion.

2(g) Correct calculation of F. 1

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Question Answer Marks

2(h)(i) A Two readings are not enough to draw a (valid) conclusion (not “not enough for accurate results”, “few readings”). 4

B Difficult to set up L0 with a reason e.g. because not sure/difficult to judge when the rubber band is just straight/just not
stretched.

C Difficult to measure L or L0 or length of rubber band with reason e.g. because of parallax error/measuring to curved
edge or surface.

D No account of thickness change e.g. not measuring thickness change.

E Difficult to measure w, w0 or t with a reason e.g. micrometer squashes the rubber band because it is not rigid.

F Difficult to manipulate micrometer to measure t when rubber band is positioned between the clamps.

1 mark for each point up to a maximum of 4.

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Question Answer Marks

2(h)(ii) A Take more readings (for different values of L) and plot a graph or take more readings and compare k values (not 4
“repeat readings” on its own).

B Hang rubber band from newton meter (to check not under tension).

C Use calipers (to measure L or L0)

or
use clamped rule (with pointers)
or
use thinner rods.

D Measure thickness when stretched/loaded/under tension.

E Lay rubber band flat on surface to measure w0

or
remove rubber band to measure t
or
use travelling microscope.

F Measure multiple thicknesses nt (and divide by n).

1 mark for each point up to a maximum of 4.

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