Cambridge A Level Physics 9702 — 2016 Oct/Nov Paper 3 · Variant 1

This document consists of 13 printed pages and 3 blank pages. DC (RW/FD) 117493/3 © UCLES 2016 [Turn over Cambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level * 5 1 7 9 3 2 1 9 7 8 * PHYSICS 9702/31 Paper 3 Advanced Practical Skills 1 October/November 2016 2 hours Candidates answer on the Question Paper. Additional Materials: As listed in the Confidential Instructions. 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 an HB pencil for any diagrams or graphs. Do not use staples, paper clips, 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 are reminded of the need for good English and clear presentation in your answers. Electronic calculators may be used. 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. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use 1 2 Total

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3 9702/31/O/N/16 © UCLES 2016 [Turn over You may not need to use all of the materials provided. 1 In this experiment, you will investigate the motion of a mass attached to a system of springs. (a) (i) Set up the apparatus as shown in Fig. 1.1. clip A clip B ring string loop spring 50 cm bench G-clamps stand 400 g mass K K spring stand Fig. 1.1 Slide the string loop over the rod of a stand and fix it in place near the top of the rod with one of the clips. Slide the free loop of the spring over the other rod and fix it in place with the other clip. The string loop in clip A is a height h above the base of the stand and the spring loop in clip B is a height h1 above the base of the stand. Adjust the apparatus until h and h1 are equal. (ii) Measure and record h. h = …

4 9702/31/O/N/16 © UCLES 2016 (b) Pull the 400 g mass down through a short distance. Release the mass. The mass will oscillate. Determine the period T of these oscillations. T = …[2] (c) The period T of the oscillation of a mass m attached to a system of springs is given by T = 2π m k where k is the spring constant of the system. The mass m is 0.400 kg. Using your answer in (b), calculate the corresponding value of k. Give your answer to an appropriate number of significant figures. k = …N m–1 [2]

5 9702/31/O/N/16 © UCLES 2016 [Turn over (d) (i) Slide the spring loop in clip B down by approximately 5 cm as shown in Fig. 1.2. Do not move clip A. clip A clip B K Fig. 1.2 The spring loop in clip B is a height h1 above the base of the stand. (ii) Measure and record h1. h1 = … (iii) Calculate (h – h1). (h – h1) = … (iv) Repeat (b). T = …

6 9702/31/O/N/16 © UCLES 2016 (e) Vary h1 and repeat (d)(ii), (d)(iii) and (b) until you have six sets of values of (h – h1) and T. Do not move clip A. Include in your table the two sets of values already taken. [8] (f) (i) Plot a graph of T on the y-axis against (h – h1) on the x-axis. [3] (ii) Draw the straight line of best fit. [1] (iii) Determine the gradient and y-intercept of this line. gradient = … y-intercept = … [2]

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8 9702/31/O/N/16 © UCLES 2016 (g) It is suggested that the quantities T and h1 are related by the equation T = P(h – h1) + Q where P and Q are constants. Using your answers in (f)(iii), determine the values of P and Q. Give appropriate units. P = … Q = … [2] [Total: 20]

9 9702/31/O/N/16 © UCLES 2016 [Turn over You may not need to use all of the materials provided. 2 In this experiment, you will investigate the potential difference across a current-carrying wire. (a) You have been provided with a wooden strip with wires attached. The wire attached between A and B has a diameter D. (i) Without detaching the wire from the board, measure and record D. D = …[1] (ii) Estimate the percentage uncertainty in your value of D. percentage uncertainty = …[1]

10 9702/31/O/N/16 © UCLES 2016 (b) Set up the circuit shown in Fig. 2.1. V A d.c. supply crocodile clip crocodile clip A B C E Fig. 2.1 The crocodile clips should be connected to A and C. (c) (i) Adjust the rheostat to approximately the middle of its range. (ii) Close the switch. (iii) Record the ammeter reading. ammeter reading = …[1] (iv) Record the voltmeter reading V. V = …[1] (v) Open the switch.

11 9702/31/O/N/16 © UCLES 2016 [Turn over (d) (i) The wire attached between B and C has a diameter d. Measure and record d. d = …[1] (ii) Calculate G where G = D 2 + d 2 D 2d 2 . G = …[1] (iii) Justify the number of significant figures that you have given for your value of G. … … …[1]

12 9702/31/O/N/16 © UCLES 2016 (e) (i) Disconnect the crocodile clip from C and connect it to E. (ii) Close the switch. (iii) Adjust the rheostat so that the ammeter reading is the same as in (c)(iii). (f) (i) Repeat (c)(iv) and (c)(v). V = …[2] (ii) The wire attached between B and E has diameter d. Measure and record d and calculate G. d = … G = … [1]

13 9702/31/O/N/16 © UCLES 2016 [Turn over (g) It is suggested that the relationship between V and G is V = kG where k is a constant. (i) Using your data, calculate two values of k. first value of k = … second value of k = … [1] (ii) Explain whether your results support the suggested relationship. … … … …[1]

14 9702/31/O/N/16 © UCLES 2016 (h) (i) Describe four sources of uncertainty or limitations of the procedure for this experiment. 1. … … 2. … … 3. … … 4. … … [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. … … [4] [Total: 20]

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16 9702/31/O/N/16 © UCLES 2016 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. To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after the live examination series. 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. BLANK PAGE

® IGCSE is the registered trademark of Cambridge International Examinations. This document consists of 4 printed pages. © UCLES 2016 [Turn over Cambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level PHYSICS 9702/31 Paper 3 Advanced Practical Skills 1 October/November 2016 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 will not enter into discussions about these mark schemes. Cambridge is publishing the mark schemes for the October/November 2016 series for most Cambridge IGCSE®, Cambridge International A and AS Level components and some Cambridge O Level components.

Page 2 Mark Scheme Syllabus Paper Cambridge International AS/A Level – October/November 2016 9702 31 © UCLES 2016 1 (b) Value for T in the range 0.60 s to 0.80 s with unit. [1] Evidence of repeat timings (at least two recordings of nT where n ⩾ 5). [1] (c) Correct calculation of k. [1] Value of k must be given to the same number of s.f. as (or one more than) the s.f. in the values of the raw times. [1] (e) Six sets of readings of (h – h1) and T (with correct trend and without help from Supervisor) scores 5 marks, five sets scores 4 marks etc. [5] Range: [1] ∆(h – h1) ⩾ 30.0 cm. Column headings: [1] Each column heading must contain a quantity and a unit where appropriate. The presentation of the quantity and unit must conform to accepted scientific convention, e.g. T / s or T (s). Consistency: [1] All values of (h – h1) must be given to the nearest mm. (f) (i) Axes: [1] Sensible scales must be used. Awkward scales (e.g. 3:10, fractions or non-linear) are not allowed. Scales must be chosen so that the plotted points occupy at least half the graph grid in both x and y directions. Scales must be labelled with the quantity that is being plotted. Scale markings should be no more than three large squares apart. Plotting of points: [1] All observations must be plotted on the grid. Diameter of plotted points must be ⩽ half a small square (no “blobs”). Points must be plotted to an accuracy of half a small square. Quality: [1] All points in the table must be plotted on the grid for this mark to be awarded. All points must be within 0.01 s on the y-axis of a straight line. (ii) Line of best fit: [1] Judge by balance of all points on the grid about the candidate’s line (at least 5 points). There must be an even distribution of points either side of the line along the full length. Allow one anomalous point only if clearly indicated (i.e. circled or labelled) by the candidate. There must be at least five points left after the anomalous point is disregarded. Line must not be kinked or thicker than half a small square.

Page 3 Mark Scheme Syllabus Paper Cambridge International AS/A Level – October/November 2016 9702 31 © UCLES 2016 (iii) Gradient: [1] The hypotenuse of the triangle must be greater than half the length of the drawn line. The method of calculation must be correct. Do not allow ∆x / ∆y. Both read-offs must be accurate to half a small square in both the x and y directions. y-intercept: [1] Either: Check correct read-off from a point on the line and substituted into y = mx + c. Read-off must be accurate to half a small square in both x and y directions. Or: Check read-off of the intercept directly from the graph (accurate to half a small square. (g) Value of P = candidate’s gradient and value of Q = candidate’s intercept. [1] Do not allow fractions. Units for P (e.g. s m–1 or s cm–1 or s mm–1) and Q (s) correct. [1] 2 (a) (i) Value for D with unit in the range 0.14 mm to 0.16 mm. [1] (ii) Percentage uncertainty in D based on an absolute uncertainty of 0.01 mm. Correct method of calculation to obtain percentage uncertainty. [1] (c) (iii) Value of I in range 10 mA ⩽ I ⩽ 200 mA with unit (collected without help from Supervisor). [1] (iv) Value of V in range 0.4 V ⩽ V ⩽ 1.0 V with unit (collected without help from Supervisor). [1] (d) (i) Value of d > D and d < 1 mm. [1] (ii) Correct calculation of G. [1] (iii) Justification for s.f. in G linked to s.f. in D and d. [1] (f) (i) Second value of V. [1] Quality: second value of V less than first value of V. [1] (ii) Second value of d. [1]

Page 4 Mark Scheme Syllabus Paper Cambridge International AS/A Level – October/November 2016 9702 31 © UCLES 2016 (g) (i) Two values of k calculated correctly, and to at least 2 significant figures. [1] (ii) Valid comment consistent with calculated values of k, testing against a stated numerical criterion. [1] (h) (i) Limitations [4] (ii) Improvements [4] Do not credit A Two readings not enough to draw a conclusion Take many readings (for different diameters) and plot a graph/ take more readings and compare k values Two readings not enough for accurate results Repeat readings Few readings Take more readings and calculate average k B Difficult to measure diameter(s) with reason e.g. awkward placing micrometer round wire/ only one direction to measure diameter Provide separate lengths of wire C Meter readings changed in a particular direction over time/ repeat readings of I or V were often different/ contact resistance varies Use power supply/ allow reading to reach steady value/ method of cleaning crocodile clips or wires D Wire is very thin introducing a large percentage error in the diameter Use thicker wire/ use digital micrometer E Rheostat movement not precise enough – overshot I reading Method to ensure exact current easier to produce e.g. use of screw thread adjustment