HCI 2026 C2 Prelim Paper 4 QP

This document consists of 16 printed pages and 2 blank pages. HWA CHONG INSTITUTION Preliminary Examination Higher 2 CANDIDATE NAME CT GROUP 2 5 S CENTRE NUMBER INDEX NUMBER PHYSICS Paper 4 Practical Candidates answer on the Question Paper. Additional Materials: As listed in the Confidential Instructions. 9478/04 27 August 2026 2 hours 30 minutes READ THESE INSTRUCTIONS FIRST Shift Laboratory For Examiner’s Use 1 / 11 2 / 15 3 / 24 Total / 50 Write your particulars clearly in the spaces at the top of this page. Write and shade your Student ID using a 2B pencil. You may lose marks if you do not show your working or if you do not use appropriate units. • Answer all questions. • Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs. • Write your answer to each question in the space provided. • Do not use an erasable pen. Do not use correction fluid or tape. • You may use an approved calculator. • You may use a spreadsheet to process and analyse data. • Write the details of the shift and laboratory in the boxes provided. • You will be allowed to work with the apparatus for a maximum of 1 hour and 15 minutes for each section. INFORMATION • The total mark for this paper is 50. • The number of marks for each question or part question is shown in brackets [ ].

2 © Hwa Chong Institution 2026 9478/04/C2 Preliminary Examination DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN Section A 1 This experiment considers the forces on a setup of springs. (a) You have been provided with three identical springs, attached to a ring. The length of an unstretched spring is S, as shown in Figure 1.1. Without disconnecting the springs, measure and record S for one of the springs. Figure 1.1 S = …………………………. [1] 1 Fig. 1.1 The length of the unstretched spring is S, as shown in Fig. 1.2. Fig. 1.2 Measure and record L and S. L = …………………………. S = …………………………. [1]

3 © Hwa Chong Institution 2026 9478/04/C2 Preliminary Examination DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN [Turn over (b) Set up the apparatus as shown in Figure 1.2. Figure 1.2 Set m = 200 g. Adjust the apparatus so that the angle between the springs is 90°. The extended length of the double spring is S1 and the extended length of the single spring is S2. (i) Measure and record S1 and S2. S1 = …………………………. S2 = …………………………. [1] (ii) The extensions are p and q, where =− 1 2p S S and =− 2q S S Calculate p and q. p = …………………………. q = …………………………. [1]

4 © Hwa Chong Institution 2026 9478/04/C2 Preliminary Examination DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN (iii) Calculate + 2 2()4p q . + 2 2()4p q = …………………………. m2 [1] (c) Vary the mass m by increasing the mass. Adjust the apparatus so that the angle between the springs is 90°. Repeat 1(b)(i), (b)(ii) and (b)(iii). Present your results clearly. [3]

5 © Hwa Chong Institution 2026 9478/04/C2 Preliminary Examination DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN [Turn over (d) Theory suggests that += 22 22 2()4pg qm k where g is 9.81 N kg-1 and k is the spring constant of one of the springs. Plot a suitable graph using a spreadsheet to determine k. Sketch the graph in the space below. Write down the equation of the trendline. k = …………………………. [3] (e) The experiment is to be conducted using 3 identical stiffer springs with spring constant 2k. State the expected change to the graph in (d). …………………………………………………………………………………………………......... …………………………………………………………………………………………………......... …………………………………………………………………………………………………......... …………………………………………………………………………………………………… [1] [Total: 11]

6 © Hwa Chong Institution 2026 9478/04/C2 Preliminary Examination DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN 2 This investigation considers the current in an RC circuit when a capacitor of capacitance C charges and discharges. Set up the circuit shown in Figure 2.1, taking care to connect the capacitor the right way round. Switch S is initially unconnected. (a) (i) Set switch S to position 1 and wait about 20 s. Record the reading I on the ammeter I = …………………………………………. [1] (ii) Set switch S to position 2 and immediately start the stopwatch. Record I every 10 s from time t = 0 to t = 50 s. Tabulate your results. You may need several attempts before you have a complete set of results. [2] (iii) Describe one problem in taking the readings. …………………………………………………………………………………………….. …………………………………………………………………………………………. [1] Figure 2.1

7 © Hwa Chong Institution 2026 9478/04/C2 Preliminary Examination DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN [Turn over (b) An engineer wants to test the capacitance of an unmarked capacitor in order to design a circuit to filter noise from received signals. To determine the properties of the circuit, the engineer connects the discharged capacitor in series with a resistor and a DC voltage supply. At time t0, the switch is closed to begin charging the capacitor, and the current in the circuit is recorded over time. During charging, the current 𝐼 decreases exponentially with time 𝑡 from its initial peak value 𝐼0 according to: II −= − 00 ( )tte where  is the time constant of the charging circuit and to is the start time of charging. The engineer’s charging data is recorded in the digital file: datasetQ2b.xlsx. (i) Use the engineer’s data to determine t0 and I0. t0 = ……………………………………… I0 = ……………………………………… [1] (ii) Use the engineer’s data to estimate the total charge Q stored in the capacitor when it is fully charged. Q = ……………………………………… [1] (iii) Explain how you obtained the value of Q. …………………………………………………………………………………………….. …………………………………………………………………………………………. [1] (iv) Plot a suitable graph using a spreadsheet to determine the time constant  of the engineer’s charging circuit. Sketch the graph in the space below. Write down the equation of the trendline.  = …………………………………………. [2]

8 © Hwa Chong Institution 2026 9478/04/C2 Preliminary Examination DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN DO NOT WRITE IN THIS MARGIN (c) The electric potential energy U stored in a capacitor of known capacitance C is given by: 21 2=U CV where V is the potential difference (p.d.) across the capacitor. Plan an investigation to determine the difference between the energy stored on the fully charged capacitor in Figure 2.1 and the work done by the cell in fully charging the capacitor. You are not required to do this experiment. Include in your plan: