Cambridge A Level Physics 9702 — 2005 Oct/Nov Paper 5 · Variant 1

This document consists of 9 printed pages and 3 blank pages. SPA (MML 8097 3/04) S88388/1 © UCLES 2005 [Turn over UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certificate of Education Advanced Level PHYSICS 9702/05 Paper 5 Practical Test October/November 2005 1 hour 30 minutes Candidates answer on the Question Paper. Additional Materials: As specified 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 in the spaces provided on the Question Paper. You may use a soft pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. Answer both questions. 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. The working of the answers is to be handed in. Marks are mainly given for a clear record of the observations actually made, for their suitability and accuracy, and for the use made of them. Additional answer paper and graph paper should be submitted 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. Centre Number Candidate Number Name If you have been given a label, look at the details. If any details are incorrect or missing, please fill in your correct details in the space given at the top of this page. Stick your personal label here, if provided. For Examiner’s Use 1 2 Total

It is recommended that you spend about 60 minutes on this question. 1 In this question you will investigate how the period of oscillation of a mass suspended from a chain of springs depends on the number of springs in the chain. (a) Clamp the base of the stand to the bench. Suspend six springs in a chain from a clamp mounted on the stand. You should use small hooks to connect the springs to one another. Suspend the 100 g mass from the bottom spring. It will be necessary to allow the chain of springs to overhang the edge of the bench. The arrangement should be as shown in Fig. 1.1. Fig. 1.1 G-clamp 100 g mass 2 For Examiner’s Use 9702/05/O/N/05 © UCLES 2005

(b) (i) Gently displace the mass and release it so that it performs vertical oscillations. Make measurements to determine the period T of the oscillations. T = … s (ii) Estimate the number of oscillations that would need to be timed in order to make the percentage uncertainty in T equal to 1%. Show your working. number of oscillations = … 3 [Turn over For Examiner’s Use 9702/05/O/N/05 © UCLES 2005

(c) Remove one of the springs from the chain and repeat (b)(i). Repeat this process until you have six sets of readings of T and n, where n is the number of springs in the chain. Include all six sets of values of lg (T / s) and lg n in your table of results. (d) (i) Plot a graph of lg (T / s) (y-axis) against lg n (x-axis). (ii) Draw the line of best fit. (iii) Determine the gradient and the y-intercept of this line. gradient = … y-intercept = … 4 For Examiner’s Use 9702/05/O/N/05 © UCLES 2005

5 [Turn over For Examiner’s Use 9702/05/O/N/05 © UCLES 2005

(e) The expression relating T and n is T = pnq where p and q are constants. Use your answers from (d)(iii) to determine values for p and q. You need not be concerned with the units of these quantities. p = … q = … (f) It can be shown that where m = 0.100 kg and k is the spring constant of each of the springs in the chain. Determine a value for k. Include an appropriate unit with your value. k = … 4
2m p = √––––– k 6 For Examiner’s Use 9702/05/O/N/05 © UCLES 2005

It is recommended that you spend about 30 minutes on this question. 2 A hot wire in air loses energy. Some of the energy is lost to the air particles that hit the wire. This energy lost depends on the number of particles hitting the wire per second, and hence on the air pressure. If the temperature of the wire is constant then the total energy lost per second is equal to the electrical energy supplied per second. Design a laboratory experiment to investigate how the total energy lost per second from a wire depends on the air pressure. You should draw a detailed labelled diagram showing the arrangement of your equipment. In your account you should pay particular attention to (a) the procedure to be followed, (b) how the electrical energy supplied to the wire per second would be measured, (c) the type of thermometer used to check that the temperature of the wire remains constant during the experiment, (d) how the pressure would be changed and measured, (e) any safety precautions that you would take. 8 For Examiner’s Use 9702/05/O/N/05 © UCLES 2005

Diagram … … … … … … … … … 9 [Turn over For Examiner’s Use 9702/05/O/N/05 © UCLES 2005

… … … … … … … … … … … … … … … … … … … … … … … … … … … … 10 For Examiner’s Use 9702/05/O/N/05 © UCLES 2005

BLANK PAGE 12 9702/05/O/N/05 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 University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.

UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS GCE Advanced/Advanced Subsidiary Level MARK SCHEME for the November 2005 question paper PHYSICS 9702/05 Paper 5 maximum raw mark 30 This mark scheme is published as an aid to teachers and students, to indicate the requirements of the examination. It shows the basis on which Examiners were initially instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners’ meeting before marking began. Any substantial changes to the mark scheme that arose from these discussions will be recorded in the published Report on the Examination. All Examiners are instructed that alternative correct answers and unexpected approaches in candidates’ scripts must be given marks that fairly reflect the relevant knowledge and skills demonstrated. Mark schemes must be read in conjunction with the question papers and the Report on the Examination. The minimum marks in these components needed for various grades were previously published with these mark schemes, but are now instead included in the Report on the Examination for this session. • CIE will not enter into discussion or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the November 2005 question papers for most IGCSE and GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.

Page 1 Mark Scheme Syllabus Paper GCE A/A LEVEL – November 2005 9702 05 © University of Cambridge International Examinations 2005 1 (b) (i) Repeated readings of raw times [1] (ii) Absolute uncertainty in t (one mark) [2] Working to get the number of oscillations for 1% uncertainty (one mark). (c) Readings [3] 6 sets scores one mark. Allow more than 6 sets without penalty. lg (T/s) and lg n correct; one mark each. Values must be checked. Minor help from the Supervisor, -1. Major help, then -2. If help has been given then write SR at the top of the front page of the script, and give a brief explanation of the type of help that has been given by the table of results. Most raw times > 10 s [1] Quality of results [1] Judge by scatter of points about the line of best fit. Column headings [1] Each column heading must contain a quantity and a unit. There must be some distinguishing feature between the quantity and the unit. Consistency of raw readings [1] All the raw readings of t should be given to the same number of d.p. (d) (i) Axes [1] The axes must be labelled with the quantities plotted. Ignore units on the axes. The plotted points must occupy at least half the graph grid in both the x and y. directions (i.e. 4 large squares in the x-direction and 6 large squares in the y-direction). Do not allow more than 3 large squares between the labels on an axis. Do not allow awkward scales (e.g. 3:10, 6:10 etc.). Plotting of points [1] All the observations must be plotted. Count the number of plots and ring this total on the grid. Do not allow plots in the margin area. Check one suspect plot. Circle this plot. Tick if correct. If incorrect, mark the Correct position with a small cross and use an arrow to indicate where the plot should have been, and -1. Allow errors up to and including half a small square.

Page 2 Mark Scheme Syllabus Paper GCE A/A LEVEL – November 2005 9702 05 © University of Cambridge International Examinations 2005 (ii) Line of best fit [1] Only a drawn straight line through a linear trend is allowable for this mark. This mark can only be awarded for 5 or more plots on the grid. There must be a reasonable balance of points about the drawn line. Do not allow a line of thickness greater than half a small square. (iii) Gradient [1] Ignore any units given with the value. Hypotenuse of ∆ must be > half the length of line drawn. Check the read-offs. Work to half a small square. ∆x/∆y gets zero. Values taken from the table that lie on the line to within half a small square are acceptable. (iii) y-intercept [1] (e) q = gradient [1] (e) p = 10y-intercept [1] (f) Value of k [1] Must be in range 20 to 30 N m-1 (f) Unit of k (e.g. N m-1 or kg s-2) [1] (f) sf in k (accept 2 or 3 sf only) [1] 20 marks in total

Page 3 Mark Scheme Syllabus Paper GCE A/A LEVEL – November 2005 9702 05 © University of Cambridge International Examinations 2005 2 A1 Procedure OK (i.e. measure pressure and electrical power; change pressure [1] and measure new power and repeat). This mark can be scored even if the method is unworkable. A2 Diagram of workable arrangement [2] e.g. wire connected to joulemeter and power supply. A stopwatch must be used if this method is employed. Allow alternative circuit using ammeter and voltmeter. The wire must be shown inside a closed container with some means of changing and measuring the pressure. One mark for the electrical arrangement; one mark for the mechanical arrangement. A3 Measurement of pressure [1] (e.g. Bourdon gauge/pressure gauge/manometer) B1 Change setting on the power supply to keep the wire at the same [1] temperature when the pressure is changed. B2 Power supplied to wire = V x I (or reading on joulemeter ÷ time) [1] B3 Use of thermocouple thermometer to monitor temperature whilst pressure [1] is changed or adjust V or I to keep R (and hence T) constant C Any one safety precaution [1] e.g. safety screens/goggles/wire mesh surrounding vacuum chamber D1/2 Any further good design features [2] Some of these might be: Thermocouple thermometer shown attached to the wire to monitor temperature. Light spot galvanometer connected to thermocouple. Use of a needle valve to control pressure. Vacuum grease the connecting wires to the heater wire. Allow time between readings for experiment to stabilise. Do not allow the wire to become too hot or the thermocouple may melt. 10 marks in total