Cambridge A Level Physics 9702 — 2010 May/June Paper 3 · Variant 5

This document consists of 9 printed pages and 3 blank pages. DC (CW/CGW) 23781/2 © UCLES 2010 [Turn over UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certificate of Education Advanced Subsidiary Level and Advanced Level READ THESE INSTRUCTIONS FIRST Write your Centre number, candidate number and name on all the work you hand in. Write in dark blue or black pen. You may use a soft pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. DO NOT WRITE IN ANY BARCODES. Answer both questions. You will be allowed to work with the apparatus for a maximum of one hour for each question. You are expected to record all your observations as soon as these observations are made, and to plan the presentation of the records so that it is not necessary to make a fair copy of them. You may lose marks if you do not show your working or if you do not use appropriate units. Additional answer paper and graph paper should be used only if it becomes necessary to do so. You are reminded of the need for good English and clear presentation in your answers. At the end of the examination, fasten all your work securely together. All questions in this paper carry equal marks. * 3 3 9 0 3 5 9 0 7 5 * PHYSICS 9702/35 Paper 31 Advanced Practical Skills 1 May/June 2010 2 hours Candidates answer on the Question Paper. Additional Materials: As listed in the Confidential Instructions. For Examiner’s Use 1 2 Total

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3 9702/35/M/J/10 [Turn over © UCLES 2010 For Examiner’s Use You may not need to use all of the materials provided. 1 In this experiment, you will investigate the relationship between the power dissipated in a filament lamp and the resistance of the lamp. (a) Assemble the circuit of Fig. 1.1. A V Fig. 1.1 (b) Set the power supply voltage to 12 V and close the switch so that the lamp lights. Record the voltmeter reading V and the ammeter reading I. V = … V I = … A

4 9702/35/M/J/10 © UCLES 2010 For Examiner’s Use (c) Reduce the power supply voltage, recording V and I until you have six sets of readings. Open the switch when you have finished your measurements. Include in your table of results values of P, R and R 4, where P is the power dissipated in the lamp and R is the resistance of the lamp. (P = VI and R = V I ) (d) (i) Plot a graph of P on the y-axis against R 4 on the x-axis. (ii) Draw the straight line of best fit. (iii) Determine the gradient and y-intercept of this line. gradient = … y-intercept = …

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6 9702/35/M/J/10 © UCLES 2010 For Examiner’s Use (e) It is suggested that the relationship between P and R is P = aR 4 + b where a and b are constants. Using your answers from (d)(iii), determine the values of a and b. Give appropriate units. a = … b = …

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8 9702/35/M/J/10 © UCLES 2010 For Examiner’s Use You may not need to use all of the materials provided. 2 In this experiment, you will investigate how the movement of a tube is affected by fluid friction. The apparatus has been set up for you as shown in Fig. 2.1. The mass hanger will move up and down if it is pulled down and released. oil tube spring clamp distance indicator mass hanger and masses tray Fig. 2.1 (a) (i) By adjusting the position of the clamp, lower the spring and mass hanger so that the bottom of the tube is immersed centrally in the oil to a depth d of about 5 cm, as shown in Fig. 2.2. (ii) Measure and record d. d = … d distance indicator Fig. 2.2

9 9702/35/M/J/10 [Turn over © UCLES 2010 For Examiner’s Use (b) Adjust the distance indicator so that its arrow is level with the bottom of the mass hanger, as shown in Fig. 2.2. (c) (i) Pull down the mass hanger about 3 cm and release it so that it moves up and down. Each time the mass hanger moves down, you will see that the lowest position that it reaches changes gradually from 3 cm to 0 cm below the arrow. (ii) Repeat (i) and start the stopwatch when the mass hanger’s lowest position is 2.0 cm below the arrow. Stop the stopwatch when the lowest position has become 0.5 cm below the arrow. Record this time t. t = … (d) Estimate the percentage uncertainty in t. percentage uncertainty = … (e) (i) By again adjusting the position of the clamp, lower the spring and mass hanger so that d is about 10 cm. (ii) Repeat (a)(ii), (b) and (c). d = … t = …

10 9702/35/M/J/10 © UCLES 2010 For Examiner’s Use (f) (i) It is suggested that the relationship between t and d is t 4 = k d 3 where k is a constant. Using your data, calculate two values of k. first value of k = … second value of k = … (ii) Explain whether your results support the relationship in (i). … … … (iii) Justify the number of significant figures that you have used for your values of k. … … … …

11 9702/35/M/J/10 © UCLES 2010 For Examiner’s Use (g) (i) Describe four sources of uncertainty or limitations of the procedure in this experiment. 1. … … 2. … … 3. … … 4. … … (ii) Describe four improvements that could be made to this experiment. You may suggest the use of other apparatus or different procedures. 1. … … 2. … … 3. … … 4. … …

12 9702/35/M/J/10 © UCLES 2010 BLANK PAGE Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity. University of Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.

UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS GCE Advanced Subsidiary Level and GCE Advanced Level MARK SCHEME for the May/June 2010 question paper for the guidance of teachers 9702 PHYSICS 9702/35 Paper 31 (Advanced Practical Skills), maximum raw mark 40 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 must be read in conjunction with the question papers and the report on the examination. • CIE will not enter into discussions or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the May/June 2010 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.

Page 2 Mark Scheme: Teachers’ version Syllabus Paper GCE AS/A LEVEL – May/June 2010 9702 35 © UCLES 2010 1 (c) Six sets of readings of I and V scores 5 marks, five sets scores 4 marks, etc. [5] Indicate the number of sets of readings. Incorrect trend then –1 (wrong trend P increases, R4 decreases). Apparatus correctly set up without help from supervisor. [2] Major help –2, minor help –1 Range of V: Vmin Y 2 V and Vmax [ 10 V. [1] Column headings (V/V, I/A, P/W, R/Ω, R 4/Ω4) [1] Must have V and I columns. Each column heading must contain a quantity and a unit where appropriate. Ignore units in the body of the table. There must be some distinguishing mark between the quantity and the unit (solidus is expected but accept, for example, V(V)). Consistency of presentation of raw readings. [1] All raw values of V must be given to the same number of decimal places and this must be 0.1 V. All raw values of I must be given to the same number of decimal places Significant figures. [1] S.F. for P must be the same as, or one more than, the least number of S.F. used in V or I. Check each row. Values of R4 correct. Underline and check the specified value of R4. [1] If incorrect, write in the correct value. (d) (i) Graph Axes: Sensible scales must be used, no awkward scales (e.g. 3:10). [1] Scales must be chosen so that the plotted points must occupy at least half the graph grid in both x and y directions. Indicate false origin with FO. Scales must be labelled with the quantity which is being plotted. Ignore units. Allow inverted axes but do not allow wrong graph. Scale markings should be no more than three large squares apart. Plots All observations must be plotted. Write a ringed total of plotted points. [1] Do not accept blobs (points > 0.5 small square). Ring and check a suspect plot. Tick if correct. Re-plot if incorrect. Work to an accuracy of half a small square. (ii) Line of best fit [1] Judge by balance of at least 5 trend points about the candidate’s line. There must be an even distribution of points either side of the line along the whole length. Indicate best line if candidate’s line is not the best line. Lines must not be kinked. Quality [1] Judge by scatter of all points about a straight line. All points in the table (minimum 5) must be within 50 mW of a straight line. Do not award if wrong graph or wrong trend.

Page 3 Mark Scheme: Teachers’ version Syllabus Paper GCE AS/A LEVEL – May/June 2010 9702 35 © UCLES 2010 (iii) Gradient [1] The hypotenuse of the triangle must be at least half the length of the drawn line. Both read-offs must be accurate to half a small square. If incorrect, write in correct value. Check for ∆y / ∆x (i.e. do not allow ∆x / ∆y). y-intercept from graph or substitute correct read-offs into y = mx + c [1] Label FO. (e) a = gradient value and b = y–intercept value. [1] Units for a and b are correct (expect WΩ–4 for a and W for b). [1] Range: a = 3 × 10–9 ± 1 × 10–9 or SV ± 33% [Total: 20] 2 (a) (ii) Value of d, with consistent unit. Range of d: 5 ± 1 cm [1] d to nearest mm. [1] (c) (ii) Evidence of repeated measurements of t either in (c)(ii) or (e)(ii). [1] Value of t in range 5 to 30 s. [1] (d) Absolute uncertainty in t in the range 0.5 to 1.0 s. [1] If repeated readings have been taken, then the uncertainty can be half the range. Correct calculation to get % uncertainty. [1] (e) (ii) Second value for d. [1] Second value for t. [1] Quality: t2 less than t1. [1] (f) (i) Correct calculation of two values of k or equivalent. [1] (ii) Valid conclusion based on the calculated values of k. [1] Candidate must test against a specified criterion. (iii) Justification with reference to the significant figures in t and d. [1]

Page 4 Mark Scheme: Teachers’ version Syllabus Paper GCE AS/A LEVEL – May/June 2010 9702 35 © UCLES 2010 (g) Limitations (4) Improvements (4) Ignore A Ap Two readings not enough (to support conclusion) / too few readings. As Take more (sets of) readings and plot a graph / compare values of k. Repeat readings B Bp Marker never exactly on 2 cm or 0.5 cm: either above or below / increments in changes in amplitude too large / difficult to judge 2 cm and 0.5 cm. Bs Video with timer (playback) in slow motion / position sensor above with data logger / measure the amplitudes over time. Use computer to improve the experiment. Multi-flash photography? Light gates. C Cp Straw not vertical (straight) / straw bumping into sides/ non-vertical oscillation. Cs Wider container / glue straw / method of alignment. No ref to changing oil D Dp Difficult to measure ‘d’ because of lining up meniscus / refraction of curved container. Ds Mark straw/ mark container / use travelling microscope / vernier calliper? E Ep Difficult to measure time because moves past the marker quickly / small distances involved. Es Video with timer (playback) in slow motion / position sensor above with data logger. Credit once only. [Total: 20]