AJC H2 PHY P4 Q Soln

9749/04/AJC/2017/Prelim [Turn Over 1 Name: _____________________________ ( ) PDG: ______/ 16 2017 JC2 Preliminary Examination PHYSICS Higher 2 9749/04 Paper 4 Practical Friday 25 August 2017 2 hours 30 minutes Candidates answer on the Question Paper. Additional Materials: As listed on the Confidential Instructions READ THESE INSTRUCTIONS FIRST Write your name, class index number and PDG in the spaces provided above. Write in dark blue or black pen on both sides of the paper. You may use an HB pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, glue or correction fluid. Answer all questions. Write your answers in the spaces provided on the question paper. The use of an approved scientific calculator is expected, where appropriate. You may lose mark if you do not show your working or if you do not use appropriate units. Give details of the practical shift and laboratory where appropriate in the boxes provided. 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. Shift Laboratory ANDERSON JUNIOR COLLEGE This document consists of 16 printed pages and 0 blank page. For Examiner’s Use Paper 4 (55 marks) 1 2 3 4 Total (55 marks)

9749/04/AJC/2017/Prelim 2 1 In this experiment, you will investigate how the per iod of torsional oscillations of a bar magnet suspended above a fixed bar magnet changes with the separation between the two magnets. (a) (i) Fix one of the magnets to the bench top using Blu-tack. (ii) Suspend a second magnet using a stirrup and thread so that it lies in a horizontal plane about 50 cm below the point of suspension. The distance d between the bottom of the suspended magnet and the top of the fixed magnet should initially be about 5 cm. The base of the stand should be as far as possible from the fixed bar magnet. The arrangement is shown in Fig. 1.1. Fig. 1.1 (b) (i) Measure and record distance d. d = …..…………….…………. [1] (ii) Estimate the percentage uncertainty in d, showing your working. percentage uncertainty =…..…………….…………. [1] For Examiner’s Use M1 about 50 cm cotton suspended bar magnet fixed bar magnet point of suspension small block of wood d A1 about 50 cm cotton suspended bar magnet fixed bar magnet using blu-tack point of suspension small block of wood d

9749/04/AJC/2017/Prelim [Turn Over 3 (iii) Gently rotate the suspended magnet and release it so that it performs small torsional oscillations in a horizontal plane, as shown in Fig. 1.2. Fig.1.2 Make and record measurements to determine the period T of these oscillations. T = …..…………….…………. [2] (c) It is suggested that period T is proportional to separation d. Change d to a value between 3 cm to 10 cm and take another set of measurements to investigate this suggestion. State and explain whether or not you agree with this suggestion. Present your measurements and calculated results clearly. …………………………………………...………………………………………………………... …………………………………...………………………………………………………………... …………………………………...………………………………………………………………... ………………………………………..…………………………………………………….……... …………………………………………..…………………………………………………….…... ……………………………………………….…………………………………………………. [5] For Examiner’s Use A2 M3 A3 A4 A5 A6 top view M2

9749/04/AJC/2017/Prelim 4 (d) Explain why, in practice, it may be difficult to measure the period T directly for a separation d = 1 cm. …………………………………………..…………………………………………………….…... ……………………………………………….…………………………………………………. [1] (e) A student suggests that the period of torsional oscillations T depends on the mass distribution of the oscillating body about its axis of rotation. Suggest changes that could be made to the setup in Fig. 1.1 to study the student’s claim when two lumps of plasticine of equal mass are provided. …………………………………...………………………………………………………………... ………………………………………..…………………………………………………….……... …………………………………...………………………………………………………………... …………………………………...………………………………………………………………... ………………………………………..…………………………………………………….……... ……………………………………………….…………………………………………………. [3] [Total: 13 marks] A7 PL1 PL2 PL3 For Examiner’s Use

9749/04/AJC/2017/Prelim [Turn Over 5 2 This investigation considers how the force required to maintain equilibrium of a horizontal rule depends on the position of a mass suspended from the rule. (a) (i) Suspend a metre rule horizontally using two loops of string and a newton-meter, as shown in Fig. 2.1. The strings must be vertical. Fig. 2.1 (ii) Suspend the 50 g mass at a distance d from the newton-meter using a loop of string. You will need to adjust the position of the clamps to ensure that the rule remains horizontal. The arrangement should now be as shown in Fig. 2.2. Fig. 2.2 (b) (i) Measure and record the value of d and the reading F from the newton-meter. d =……..………..… F =……..………..…[1] For Examiner’s Use M1 newton-meter string string stand rule

9749/04/AJC/2017/Prelim 6 (ii) Slide the suspended mass to a new position on the rule and repeat (b)(i). Record at least five more readings of d and F. You should ensure when you are taking readings that the rule is horizontal and that the newton-meter does not go off scale. [3] (iii) Explain how you ensured that the rule was horizontal when the measurements were taken. …..………………………………………………………………………………………..… …..…………………………………………………………………………………….….… …………………………………………………………… ………………………...….…[1] (c) Plot your values from (b)(ii) on Fig. 2.3. Fig. 2.3 [2] For Examiner’s Use P1 P2 A1 M2 M3 M4 1.0 0.8 F / N 0.6 0.4 0.2 0 20 40 60 80 100 d / cm

9749/04/AJC/2017/Prelim [Turn Over 7 (d) The equation that relates F and d is Wmg L WdF  2 where W is the weight of the suspended mass, m is the mass of the rule, L = 0.980 m, and g = 9.81 m s-2. Use your graph of Fig. 2.3 to determine value for m. Include appropriate unit. m =……..………..…[3] [Total: 10 marks] For Examiner’s Use A2 A3 A4

9749/04/AJC/2017/Prelim 8 3 In this experiment, you will determine the resistivity of a metal in the form of a wire. (a) (i) Measure and record the diameter d of the wire attached to the metre rule. d = …..…………….…………. [1] (ii) Calculate the cross-sectional area A of the wire. A =…………………..……m 2 [1] (b) (i) Use the wire attached to the metre rule, one of the voltmeters and one of the two identical resistors of resistance R to set up the partial circuit shown in Fig. 3.1. The value of R is 10 . There are two crocodile clips, one labelled K and the other labelled L. Place K and L so that the distance l between them is approximately 30 cm. (ii) Measure and record the distance l between K and L. l = ………..………………..…… Fig. 3.1 M1 R A1 For Examiner’s Use

9749/04/AJC/2017/Prelim [Turn Over 9 (iii) Use the other resistor and the other voltmeter to complet