CJC.H2.PRELIM.2023.P4.Suggested_Solutions

Catholic Junior College JC2 Preliminary Examinations Higher 2 CANDIDATE NAME Suggested Solutions CLASS 2T INDEX NUMBER PHYSICS 9749/04 Paper 4 Practical 21 Aug 2023 2 hour 30 minutes Candidates answer on the Question Paper READ THESE INSTRUCTIONS FIRST Write your name and class on all the work you hand in. Write in dark blue or black pen on both sides of the paper. You may use an HB or 2B 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 marks 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 assessment, fasten all your work securely together. The number of marks is given in brackets [ ] at end of each question or part question. This document consists of 15 printed pages and 1 blank page. Shift Laboratory For Examiner’s Use 1 / 15 2 / 6 3 / 22 4 / 12 Total / 55

2 BLANK PAGE This paper is the 2020 A-level Paper. Please refer to the Confidential Instructions on the preparation of the apparatus

3 [Turn Over 1. In this experiment, you will investigate the current in an electrical circuit. (a) You have been provided with two metre rules A and B, each with a resistance wire attached. Take measurements to determine the resistance per unit length of each of the wires. The resistance per unit length of the wire attached to rule A is RA. The resistance per unit length of the wire attached to rule B is RB. Solution: Resistance of 100.0 cm length of wire A = 15.4 Ω RA = 15.4 / 100.0 = 0.154 Ω cm-1 Resistance of 100.0 cm length of wire B = 26.9 Ω R A = 26.9 / 100.0 = 0.269 Ω cm-1 RA = ………………0.154 Ω cm-1 or 15.4 Ω m-1…..….….……….. RB = ………………0.269 Ω cm-1 or 26.9 Ω m-1…..….….……….. [2] (b) Set up the circuit as shown in Fig. 1.1. L should be approximately half the length of the rule and x should be greater than L. Close the switch. Measure and record L, x and the ammeter reading I. L = ………………50.0 cm…..….….……….. x = ………………55.0 cm…..….….……….. I = ………………0.243 A……..….….……... (c) Vary x, obtaining a suitable range of values between 0 cm and 100 cm, repeat (b), keeping L constant throughout. Fig. 1.1

4 Solution: x / cm I / A x 1 / cm-1 55.0 0.243 0.0182 63.0 0.231 0.0159 70.0 0.226 0.0143 78.0 0.216 0.0128 85.0 0.212 0.0118 90.0 0.211 0.0111 [3] (d) It is suggested that I and x are related by the e