Physics 9702/51 October/November 2023: question paper and mark scheme
Cambridge AS & A Level Physics (9702), Paper 5 Planning, Analysis and Evaluation, October/November 2023. Read both free below, or download them. Done the paper? Get it marked by AI against this mark scheme.
Two coils, C and D, are placed with their axes on a straight line, as shown in Fig. 1.1.
R coil D
coil C
Fig. 1.1
A resistor of resistance R is connected in series with coil C.
A changing magnetic flux of frequency f in coil C causes an electromotive force (e.m.f.) E to be induced across the terminals of coil D.
It is suggested that E is related to f by the relationship pf qV
E= R
where V is the potential difference across the resistor and coil C, and p and q are constants.
Plan a laboratory experiment to test the relationship between E and f.
Draw a diagram showing the arrangement of your equipment.
Explain how the results could be used to determine values for p 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.
f is the independent variable and E is the dependent variable or vary f and measure E 1
keep V and R constant 1
Methods of data collection
labelled diagram of workable experiment including: 1
• coils C and D placed with their axes on a straight line
• separate workable circuit for coil D
• (a.c.) voltmeter or oscilloscope connected across coil D
(Do not accept a power supply connected to coil D.)
a.c. power supply/signal generator connected to coil C 1
workable circuit for coil C with power supply and (a.c.) voltmeter/oscilloscope in parallel with resistor and coil C 1
method to determine f, e.g. read from signal generator or use of oscilloscope 1
Method of Analysis
plot a graph of lg E against lg f or equivalent (e.g. ln E against ln f) 1
q = gradient 1
R 1
p= × 10y -intercept
V
R
(for ln E against ln f: p = × ey -intercept )
V
1 Additional detail including safety considerations 6
D1 precaution (to prevent burns) from hot coils/hot resistor, e.g. use gloves to handle hot coil/resistor, switch off circuit
and wait for hot coil/resistor to cool
D2 keep the number of turns on each coil constant
D3 keep distance between the coils constant
D4 workable circuit diagram to determine R. e.g. circuit with ammeter connected in series and voltmeter in parallel with
resistor
or
resistor connected to ohmmeter only
D5 determination of resistance R:
potential difference across R ÷ current in R
or
use ohmmeter to measure R
D6 method to keep distance between the coils constant, e.g. fix/clamp coils to bench
D7 method to determine f from oscilloscope, e.g. period T = time-base × horizontal distance and f = 1 / T
D8 method to determine V or E from oscilloscope, e.g. V or E = y-gain × vertical distance
D9 method to increase E e.g. use iron core, place coils closer, increase V, decrease R
D10 relationship valid if a straight line is produced (passing through log pV )
R
Do not accept line passing through the origin.
A block of modelling clay of mass M is attached to a string as shown in Fig. 2.1.
string
block pellet h
pellet
Fig. 2.1
A pellet travelling at speed u enters the block and causes the block to move through a vertical height h.
The experiment is repeated for different values of M.
It is suggested that h and M are related by the equation
M+Z 2
= 2g c m
1 h uZ
where g is the acceleration of free fall and Z is a constant.
1
(a) A graph is plotted of on the y-axis against M on the x-axis. h
Determine expressions for the gradient and y-intercept.
gradient = ……
y-intercept = ……
[1]
(b) Values of M and h are given in Table 2.1.
Table 2.1
M/g h / cm 1 1
/ cm - 2 h
565 21.0 ± 0.2
637 17.8 ± 0.2
675 16.2 ± 0.2
723 14.6 ± 0.2
790 12.6 ± 0.2
892 10.2 ± 0.2
1 1
Calculate and record values of / cm - 2 in Table 2.1. h
1
Include the absolute uncertainties in . [2]
h
1 1
(c) (i) Plot a graph of / cm - 2 against M / g. h
1
Include error bars for . [2]
h
(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]
0.32
0.31
1 1
/ cm - 2 h
0.30
0.29
0.28
0.27
0.26
0.25
0.24
0.23
0.22
0.21
550 600 650 700 750 800 850 900
M/g
(iv) Determine the y-intercept of the line of best fit. Include the absolute uncertainty in your answer.
y-intercept = …… [2]
(d) (i) Using your answers to (a), (c)(iii) and (c)(iv), determine the values of u and Z. Include appropriate units.
Data: g = 981 cm s–2
u = ……
Z = ……
[2]
(ii) Determine the percentage uncertainty in Z.
percentage uncertainty in Z = …… % [1]
(e) The experiment is repeated. Determine the mass M that gives a value of h of 25.0 cm.
M = …… g [1]
[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) 2g 1
gradient =
uZ
2g
y-intercept =
u
2(b) 1 1
1 −
/ cm 2
h
0.218 or 0.2182
0.237 or 0.2370
0.248 or 0.2485
0.262 or 0.2617
0.282 or 0.2817
0.313 or 0.3131
Values correct as shown above.
1 1
Uncertainties in from ± 0.001 to ± 0.003.
h
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.
1 1
Error bars in plotted correctly.
h
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
Do not accept line from top point to bottom point.
Points must be balanced.
Line must pass between (605, 0.230) and (615, 0.230) and between (845, 0.300) and (855, 0.300)
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 determined of worst acceptable line. 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(c)(iv) y-intercept determined by substitution of correct point with consistent power of ten into y = mx + c. 1
y-intercept of worst acceptable line determined by substitution into y = mx + c. 1
uncertainty = y-intercept of line of best fit – y-intercept of worst acceptable line
or
uncertainty = ½ (steepest worst line y-intercept – shallowest worst line y-intercept)
Do not accept ECF from false origin method.
2(d)(i) u determined using y-intercept and u and Z given to 2, 3 or 4 significant figures. 1
2 × 981 44.29
u= =
y -intercept (c)(iv)
Z determined using gradient with method shown and u and Z given with SI units with appropriate powers of ten. 1
2 × 981 44.29 y -intercept (c)(iv)
Z= = or Z = =
u × gradient u × (c)(iii) gradient (c)(iii)
2(d)(ii) Percentage uncertainty in Z with method shown. 1
Δy -intercept Δgradient
percentage uncertainty in Z = + × 100
y -intercept gradient
or
Correct substitution for Δu and
Δu Δgradient
percentage uncertainty in Z = + × 100
u gradient
or
Correct substitution for max/min methods.
2(e) M determined to a minimum of 2 significant figures from (c)(iii) and (c)(iv) or (d)(i) with correct substitution. 1
1
− y -intercept
M=
25
gradient
or
uZ uZ
M= −Z = −Z
2gh 221.5
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 9702/51 October/November 2023 mark scheme?+
On this page, free: the mark scheme for AS & A Level Physics 9702/51, October/November 2023 (9702_w23_ms_51), and the question paper (9702_w23_qp_51), to read or download, with each question's marking points written out underneath.
How many marks is 9702/51 out of?+
Physics 9702/51 for October/November 2023 is out of 30 marks, with 1 hour 15 minutes to answer it.
Can I get my 9702/51 answers marked?+
Yes. Upload your answers to 9702/51/O/N/23 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.