CHS 2022 - Sec 4 PHYSICS Prelim Exam paper 2 - Questions

Name: Index Number: Class: CATHOLIC HIGH SCHOOL Preliminary Examination Secondary 4 (O-Level Programme) PHYSICS 6091/02 Paper 2 Theory 14 September 2022 1 hour 45 minutes Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your name, index number and class on all the work you hand in. Write in dark blue or black link. You may use a HB pencil for any diagrams or graphs. Do not use paper clips, glue or correction fluid. Section A Answer all questions. Section B Answer all questions. Question 13 has a choice of parts to answer. Candidates are reminded that all quantitative answers should include appropriate units. The use of an approved scientific calculator is expected, where appropriate. Candidates are advised to show all their working in a clear and orderly manner, as more marks are awarded for sound use of Physics than for correct answers. The number of marks is given in brackets [ ] at the end of each question or part question. For examiner’s use only: Section A / 50 Section B / 30 Total / 80 Overall Marks % Paper 1 40 30% Paper 2A 50 50% Paper 2B 30 Paper 3 40 20% This document consists of 26 printed pages. 50  s.f.  formula Paper 2A

2 Section A Answer all the questions in this section. 1 Fig. 1.1 shows three forces acting on an object on a horizontal surface. Fig. 1.1 By considering the resultant of the 10 N and 15 N forces, draw a scale diagram in the space below to determine the magnitude of a fourth force that is needed to keep the object in equilibrium. force = [4] 10 N 15 N 8 N 20

3 2 Fig. 2.1 shows a cycle track. Fig. 2.1 A cyclist starts at A and follows the path ABCDEB. The speed-time graph of the cyclist is shown in Fig. 2.2. Fig. 2.2

4 (a) Using the information from both Fig. 2.1 and Fig. 2.2, describe the motion of the cyclist (i) along AB, [1] (ii) along BCDEB. [1] (b) The velocity v of the cyclist at C is shown in Fig. 2.1. State one similarity and one difference between the velocity at C and the velocity at E. similarity difference [2] (c) Calculate (i) the distance along the cycle track from A to B, distance = [1] (ii) the circumference of the circular part of the track. circumference = [1]

5 3 (a) For a special parade, the guest of honour is to sit on a chair while the parade passes by. Unfortunately, the ground beneath the chair is soft, so the parade organisers placed the chair on a large flat board, as shown in Fig. 3.1. Fig. 3.1 (i) Using ideas about pressure, explain why the board prevents the chair from sinking into the ground. [2] (ii) The mass of the chair is 10 kg, and its base area is 0.75 m2. The base area of the board is twice as large. Calculate the pressure acting on the soft ground due to the weight of the chair. The gravitational field strength g is 10 N / kg. pressure = [2]

6 (b) During the parade, some air-filled balloons are used as decorations, as shown in Fig. 3.2. Fig. 3.2 (i) State what happens to the balloons when the Sun makes them hotter. [1] (ii) Explain, in terms of molecules, your answer to (b) (i). [2] (c) A pump is used to pump up the balloons in (b). A valve in the pump becomes blocked and cannot be repaired, as shown in Fig. 3.3. Fig. 3.3 State how the pressure of the trapped air in the same pump can be reduced. [1]

7 4 (a) State what will happen to the kinetic and potential energies of the molecules of a solid when it is heated during a change of state. kinetic energy potential energy [2] (b) Most substances expand when they are heated. (i) Suggest one example where such expansion is useful. [1] (ii) State one example where such expansion could be a nuisance and hence must be considered. [1]

8 5 Fig. 5.1 shows a section through a series of waves on water. Fig. 5.1 (a) The waves enter a region of deeper water. On Fig. 5.1, carefully mark and label (i) the wavelength of the waves in the deeper water, [1] (ii) the amplitude of the waves in the deeper water. [1] (b) Describe how the frequency of the waves can be found using a stopwatch. [2]

9 6 (a) Fig. 6.1 shows a lens which forms the image of an object on a screen. Fig. 6.1 By drawing on Fig. 6.1, locate and mark the focal point of the lens with a ‘F’. [2] (b) Fig. 6.2 shows another lens that is placed in front of an object. Fig. 6.2 (i) State and explain the type of lens that is shown in Fig. 6.2. [2] (ii) By drawing on Fig. 6.2, locate and mark the image with a ‘I’. [2] object lens screen object lens

10 7 Fig. 7.1 shows a light, positively charged conducting sphere, which is hanging from an insulating thread. The sphere is deflected when a metal plate on an insulating stand is brought near the sphere. Fig. 7.1 (a) When the metal plate is touched by a finger as shown below, the sphere falls, as shown in Fig. 7.2 below. Fig. 7.2 Explain why the sphere falls. [2] insulating thread metal plate insulating stand light, positively charged conducting sphere