Physics 9702/52 October/November 2022: question paper and mark scheme
Cambridge AS & A Level Physics (9702), Paper 5 Planning, Analysis and Evaluation, October/November 2022. Read both free below, or download them. Done the paper? Get it marked by AI against this mark scheme.
A thin copper sheet is suspended from a small hole near the top of the sheet and placed in a magnetic field, as shown in Fig. 1.1.
z hole
copper sheet area A
direction of magnetic field
Fig. 1.1 (not to scale)
The sheet has area A and thickness z.
The sheet is displaced from its equilibrium position and then released so that it oscillates perpendicular to the direction of the magnetic field. The time t from when the sheet is released to when it becomes stationary is measured.
It is suggested that t is related to z by the relationship
Kz q t=
ABρ where B is the magnetic flux density of the field, ρ is the density of copper, and K and q are constants.
Plan a laboratory experiment to test the relationship between t and z.
Draw a diagram showing the arrangement of your equipment.
Explain how the results could be used to determine values for K and q.
In your plan you should include:
● the procedure to be followed
● the measurements to be taken
● the control of variables
● the analysis of the data
● any safety precautions to be taken.
Diagram
…… [15]
Mark scheme
1 Defining the problem
z is the independent variable and t is the dependent variable or vary z and measure t 1
keep B and A constant 1
Methods of data collection
labelled diagram of workable experiment including: 1
• pin/rod though hole
• supported by a stand
• sheet able to oscillate freely
• at least one label from copper/sheet, hole, clamp stand, rod, pin
use of stop-watch/timer to measure t (from release to stopping) 1
or
use of stop-watch/timer to measure time for the sheet (to stop) oscillating
use of micrometer to measure z 1
use of rule(r) to measure lengths to determine A 1
and
A = length × breadth
Method of Analysis
plot a graph of lg t against lg z or equivalent (e.g. ln t against ln z) 1
q = gradient 1
K = AB ρ × 10 y -intercept 1
( K = AB ρ × e y -intercept for ln t against ln z)
1 Additional detail including safety considerations 6
D1 use of cushion / sand box in case sheet falls
or
use gloves to protect hands from cuts / sharp edges
D2 keep (initial) distance between (copper) sheet and (poles of) magnet constant
or
keep (initial) distance between (copper) sheet and coil(s) constant
D3 keep initial displacement (of copper sheet) constant
D4 method to ensure initial displacement (of copper sheet) is constant, e.g. initially line up (corner of) plate with fiducial
marker/vertical pin
K
D5 relationship valid if a straight line (with y-intercept = log ) is produced
ABρ
D6 repeat measurements of z in different positions and average z
D7 measure B / magnetic flux density using a (calibrated) Hall probe
D8 additional detail on use of Hall probe, e.g. adjust (position of) probe until maximum value
or
measure B using Hall probe first in one direction and then in the opposite direction and average
D9 drawn method to create a magnetic field perpendicular to the area of the sheet, e.g. pair of magnets/horseshoe
magnet/pair of coils connected to a (d.c.) supply
D10 repeat experiment for each z and average t
D11 method to determine ρ, e.g. measure mass with balance and volume = Az and density = mass / volume
A student investigates stationary waves in a vertical tube using the apparatus shown in Fig. 2.1.
from signal generator to oscilloscope
loudspeaker stand tube
bench
Fig. 2.1
The student slowly increases the frequency of the signal generator from zero and listens to the sound. The loudness of the sound varies several times between minimum and maximum as the frequency is increased. The lowest frequency giving maximum loudness is identified by n = 1. The next frequencies giving maximum loudness are identified by n = 2, 3, 4, 5 and 6.
For each value of n, the student observes the trace on the oscilloscope screen. The student measures the distance d on the screen between two successive crests, as shown in Fig. 2.2.
d
Fig. 2.2
The student then determines the period T and frequency f of the signal.
It is suggested that f and n are related by the equation
(2n – 1)c f=
4h where c is the speed of sound in air and h is the height of the tube.
(a) A graph is plotted of f on the y‑axis against n on the x‑axis.
Determine expressions for the gradient and y‑intercept.
gradient = ……
y‑intercept = ……
[1]
(b) The period T and frequency f are given by the equations
1
T = d × time‑base and f = .
T
Values of n, d and the time‑base of the oscilloscope are given in Table 2.1.
Table 2.1
time‑base n d / cm T / ms f / Hz
/ ms cm–1
1 1.4 ± 0.2 5
2 2.9 ± 0.2 1
3 3.6 ± 0.2 0.5
4 2.7 ± 0.2 0.5
5 2.1 ± 0.2 0.5
6 8.8 ± 0.2 0.1
Calculate and record values of T / ms and f / Hz in Table 2.1.
Include the absolute uncertainties in T and f. [2]
(c) (i) Plot a graph of f / Hz against n. Include error bars for f. [2]
(ii) Draw the straight line of best fit and a worst acceptable straight line on your graph. Label both lines. [2]
(iii) Determine the gradient of the line of best fit. Include the absolute uncertainty in your answer.
gradient = …… [2]
1200
1100
1000
f / Hz
900
800
700
600
500
400
300
200
100
0 1 2 3 4 5 6 7 n
(d) The student measures the height of the tube. The student’s values are:
83.5 cm 82.9 cm 83.3 cm 83.1 cm.
Determine the average height h. Include the absolute uncertainty in h.
h = …… cm [1]
(e) (i) Using your answers to (a), (c)(iii) and (d), determine the value of c. Include an appropriate unit.
c = …… [2]
(ii) Determine the percentage uncertainty in c.
percentage uncertainty in c = ……% [1]
(f) The experiment is repeated with a different tube.
When n = 2, the frequency is (130 ± 5) Hz.
Determine the height h of this tube. Include the absolute uncertainty in your answer.
h = …… m [2]
[Total: 15]
To avoid the issue of disclosure of answer‑related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge
Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cambridgeinternational.org after the live examination series.
Mark scheme
2(a) c 1
gradient =
2h
c
y-intercept = −
4h
2(b) 1
T / ms f / Hz
7.0 or 7.00 ± 1 140 or 143 ± (10–30)
2.9 or 2.90 ± 0.2 340 or 345 ± (20–30)
1.8 or 1.80 ± 0.1 560 or 556 ± 30
1.4 or 1.35 ± 0.1 710 or 714 ± (40–60)
or
740 or 741
1.1 or 1.05 ± 0.1 910 or 909 ± (80–100)
or
950 or 952
0.88 or 0.880 ± 0.02 1100 or 1140 ± (30–60)
Values of T and f correct as shown above.
Absolute uncertainties in T and f correct as shown above. 1
2(c)(i) Six points from (b) plotted correctly. 1
Must be within half a small square. Diameter of points must be less than half a small square.
Error bars in f plotted correctly. 1
All error bars to be plotted. Total length of bar must be accurate to less than half a small square and symmetrical.
2(c)(ii) Straight line of best fit drawn. 1
Points must be balanced. Do not accept line from top point to bottom point.
Line must pass between (2.20, 400) and (2.40, 400) and (5.20, 1000) and (5.60, 1000).
Worst acceptable line drawn (steepest or shallowest possible line that passes through all the error bars). 1
All error bars must be plotted.
2(c)(iii) Gradient determined with clear substitution of data points into Δy / Δx. 1
Distance between data points must be greater than half the length of the drawn line.
Gradient of worst acceptable line determined with clear substitution of data points into Δy / Δx. 1
uncertainty = (gradient of line of best fit – gradient of worst acceptable line)
or
uncertainty = ½ (steepest worst line gradient – shallowest worst line gradient)
2(d) 83.2 ± 0.3 (cm) 1
2(e)(i) c determined using gradient and c given to two or three significant figures. 1
c = 2 × h × gradient = 2 × (d) × (c)(iii)
c determined using gradient and given with correct SI unit and correct power of ten: m s–1 or cm s–1. 1
2(e)(ii) Percentage uncertainty in c from (c)(iii) and (d) with method shown. 1
Δh Δgradient
percentage uncertainty = + × 100
h gradient
or
correct substitution for max/min methods:
max c = 2 × max h × max gradient
min c = 2 × min h × min gradient
2(f) h determined to at least two significant figures from (e)(i) with correct substitution. 1
3 × (e)(i)
h=
4 × 130
Absolute uncertainty in h determined. Correct substitution must be seen. 1
Δf Δc 5 Δc
Δh = + ×h = + ×h
f c 130 c
or
correct substitution for max/min methods:
3 × max c 3 × max(e)(i)
max h = =
4 × min f 4 × 125
3 × min c 3 × min(e)(i)
min h = =
4 × max f 4 × 135
Checked your answers against these? Let AI mark the whole paper, on your own working.
Examiners follow the generic marking principles at the front of the scheme, then each question's points: method (M), accuracy (A) and independent (B) marks, error carried forward where the scheme allows it, and positive marking, so you're credited for what you got right.
Check your answers against it
Done this paper? Upload your script and CIE Buddy's AI marker marks it question by question against this exact scheme, puts the ticks on your own working and says what each lost mark needed.
Where can I find the 9702/52 October/November 2022 mark scheme?+
On this page, free: the mark scheme for AS & A Level Physics 9702/52, October/November 2022 (9702_w22_ms_52), and the question paper (9702_w22_qp_52), to read or download, with each question's marking points written out underneath.
How many marks is 9702/52 out of?+
Physics 9702/52 for October/November 2022 is out of 30 marks, with 1 hour 15 minutes to answer it.
Can I get my 9702/52 answers marked?+
Yes. Upload your answers to 9702/52/O/N/22 as a PDF or photos, and CIE Buddy marks every question against this paper's official mark scheme, using Cambridge's marking rules. You get your score, each lost mark explained on your own script, and the topics to revise. It's a guide, not an official Cambridge grade.