NJC 2024 H2 Physics Prelim P4 QP

NATIONAL JUNIOR COLLEGE SENIOR HIGH 2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME SUBJECT CLASS REGISTRATION NUMBER PHYSICS Paper 4 Practical Candidates answer on the Question Paper. No Additional Materials are required. 9749/04 26 Aug 2024 2 hours 30 minutes READ THE INSTRUCTION FIRST Write your subject class, registration number and name in the spaces at the top of this page. 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 workings. 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 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 For Examiner’s Use 1 2 3 4 Total This document contains 16 printed pages and 4 blank pages. H

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3 [Turn over 1 In this experiment, you will determine the internal resistance of cell P. (a) You have been provided with two metre rules A and B, each with a 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. 𝑅𝐴 = …………………………………………………… 𝑅𝐵 = …………………………………………………… [1] (b) Setup the circuit as shown in Fig. 1.1. x y P Q K1 K2 A A

4 B Fig. 1.1 (i) Set x to 50 cm. Close switch K1 and K2. Adjust y until the ammeter reading is zero. Measure and record x and y. x = …………………………………………………… y = …………………………………………………… [2] (ii) Open switch K1 and K2. (c) Vary x and adjust y each time so that the ammeter reading is zero. x must be more than 20 cm. Present your results clearly. [4] (d) y and x are related by the expression: where a and b are constants. Plot a suitable graph to determine a and b.

5 [Turn over a = …………………………………………………… b = …………………………………………………… [7]

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7 [Turn over (e) Theory suggests that the internal resistance r of cell P is 𝑟 = 𝑎 𝑏 𝑅𝐴 Determine r. r = ……………………………………………….. [1] [Total: 15]

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9 [Turn over 2 In this experiment, you will determine the spring constant of a spring. (a) Measure and record the length 𝐿0 of the unstretched spring, as shown in Fig. 2.1. Fig. 2.1 𝐿0 = ………………………………………………. cm (b) Set up the apparatus as shown in Fig. 2.2. rod of clamp rod of clamp m retort stand retort stand red string white string P Q spring counter weight

10 θ ≈ 90 cm ≈ 75 cm L Fig. 2.2 Hang a mass m of 150 g from the red string. The distance between the two retort stands is about 90 cm. The end of the spring on the retort stand is about 75 cm from the bench. Adjust the height of Q and/or slide the red string along the white string so that the section PQ is parallel to the bench. (i) Record the value of mass m. m = ………………………………………………… g (ii) Measure and record the length L of the spring and the angle 𝜃. L = ………………………………………………. cm 𝜃 = …………………………………………………… [2] (c) Theory suggests that 𝑐𝑜𝑠 𝑐𝑜𝑠 𝜃 = 𝑚𝑔 𝑘𝑒 where k is the spring constant of the spring, e is the extension of the spring and g = 9.81 m s–2. Determine k. k = ……………………………………….. N m–1 [2] (d) If you were to repeat this experiment using other masses, describe how you will conduct the experiment and the graph that you would plot to determine k. ……………………………………………………………………………………………………………….