Compassvale 2024 Sec4Exp Prelim Phy P2

[Turn over COMPASSVALE SECONDARY SCHOOL Secondary Four Express / Five Normal (Academic) Preliminary Examination 2024 NAME CENTRE NUMBER S CLASS INDEX NUMBER PHYSICS 6091/02 Paper 2 Structured and Free Response 26 August 2024 1 hour 45 minutes Candidates answer on the Question Paper No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your name, class, Centre number and index number on all the work you hand in. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Section A Answer all questions. Write your answers in the spaces provided. Section B Answer one question. Write your answers in the spaces provided. 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. This document consists of 19 printed pages and 1 blank page. Set by: Mr E Chng

2 Section A Answer all questions. 1 Fig. 1.1 shows an oil tank. A small crack appears in an oil tank and a stream of oil is pushed out through the crack. The oil hits the floor at P where a puddle of oil starts to form. Fig. 1.1 The gravitational field strength is 10 N/kg. Atmospheric pressure is 101 kPa. (a) The density of the oil is 950 kg/m3. Calculate the total pressure exerted on the oil at the level of the crack. total pressure = ........................................ [2] (b) As time passes, the point where the oil hits the floor moves away from P. State how the oil moves and explain why this happens. ………………………………………………………………………………………………….............. ………………………………………………………………………………………………….............. ………………………………………………………………………………………………….............. …………………………………………………………………………………………………......... [2] [Total: 4] oil 3.0 m oil tank crack stream of oil P 3.5 m

3 [Turn over 2 Fig. 2.1 shows a painter standing on a wooden plank, directly above the right-hand support. Fig. 2.1 The gravitational field strength is 10 N/kg and the mass of the plank is 24 kg. (a) Determine the density of the wood from which the plank is made. density = ........................................ [2] (b) The centre of gravity of the plank is in the middle of the plank at a distance of 1.3 m from each of the supports. By considering the moments about the right-hand support, determine the value of the force F. F = ........................................ [3] (c) The man begins walking further to the right. Describe and explain what happens to the wooden plank as he does so. ………………………………………………………………………………………………….............. ………………………………………………………………………………………………….............. …………………………………………………………………………………………………......... [2] [Total: 7] wooden plank 0.35 m 3.2 m 1.3 m 0.025 m support support centre of gravity F

4 3 Ultrasound waves are used in medical imaging. To produce the image of an unborn child, an ultrasound emitter and receiver are placed close together on the mother’s skin as shown in Fig. 3.1. Fig. 3.1 (a) Ultrasound waves are a form of longitudinal waves. Explain what is meant by longitudinal waves. ………………………………………………………………………………………………….............. ………………………………………………………………………………………………….............. …………………………………………………………………………………………………......... [2] (b) Suggest why ultrasound waves are used instead of sound waves in the audible range. ………………………………………………………………………………………………….............. …………………………………………………………………………………………………......... [1] (c) Fig. 3.2 shows the pulses detected by the receiver. Pulse A is the original pulse emitted and pulse B is the pulse detected after some time. Fig. 3.2 The average speed of ultrasound in human tissue is 1500 m/s. Calculate the distance between the emitter and the child. distance = ........................................ [2] [Total: 5] emitter and receiver A B 0 0.02 0.04 0.06 0.08 time / ms

5 [Turn over 4 (a) Fig. 4.1 shows the path of a ray of red light through a piece of glass. (i) Given that the critical angle of red light is 38 °, calculate the speed of red light in the piece of glass. speed = ........................................ [2] (ii) The refractive index of blue light in glass is greater than that of red light. On Fig. 4.1 , draw a possible path for a ray of blue light through the piece of glass. Assume that the ray of blue light is also incident along AB. [1] Fig. 4.1 red light air glass A B

6 (b) Fig. 4.2 shows a scaled diagram of rays from the top of a distant object brought to focus by a converging lens, L, made from the same glass. (i) Explain how Fig. 4.2 shows that the object is a long distance away from the lens L. ……………………………………………………………………………………………………. ………………………………………………………………………………………………... [1] (ii) On Fig. 4.2, 1. mark clearly with a letter F, the position of the principal focus of the lens. [1] 2. draw two rays to show how the top of the image I is formed by the lens L. [2] [Total: 7] Fig. 4.2 converging lens L 2.0 cm principal axis image I

7 [Turn over 5 Fig. 5.1 shows the structure of a water cooler that is used to supply cold water in an office. Fig. 5.1 (a) When the tap is opened, water at room temperature from the reservoir in the plastic container flows down into the tank. Cold water from the tank flows through the plastic pipe and out of the tap. Cold liquid from the refrigeration unit is pumped through the copper pipes and thermal energy passes through the copper to this liquid. (i) Explain why the pipe is made from copper. ……………………………………………………………………………………………………. ………………………………………………………………………………………………... [1] (ii) Explain why coiled pipes are used instead of a straight pipe. ……………………………………………………………………………………………………. ………………………………………………………………………………………………... [1] (iii) As the water near the pipe cools, it begins to mix with the rest of the water in the tank. Explain how this happens. ……………………………………………………………………………………………………. ……………………………………………………………………………………………………. ………………………………………………………………………………………………... [2] cold water in reservoir of water at room temperature plastic container coiled copper pipes tap plastic pipe cold water tank refrigeration unit

8 (b) The tap is opened and water at 25 °C flows from the reservoir into the tank. The specific heat capacity of water is 4200J /(kg°C). Calculate the energy that is removed from the internal store of 250 g of this water to reduce its temperature to 10 °C. energy removed = ........................................ [2] (c) The water is poured into a cup and left on a table for some time. It was observed that some of the water evaporated. By considering the molecules in the water, explain how some of the water evaporated. ………………………………………………………………………………………………….............. ………………………………………………………………………………………………….............. ………………………………………………………………………………………………….............. …………………………………………………………………………………………………......... [2] [Total: 8]

9 [Turn over 6 Fig. 6.1 shows a potential divider made from a light-dependent resistor (LDR) and a 6.0