CAT HIGH 2025 PHY PRELIM P2 QP

Name: Index Number: Class: CATHOLIC HIGH SCHOOL Preliminary Examination Secondary 4 (O-Level Programme) PHYSICS 6091/02 Paper 2 Structured and Free Response 29 August 2025 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 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. For examiner’s use only: Section A / 70 Section B / 10 Total / 80 Overall Marks % Paper 1 40 30% Paper 2A 70 50% Paper 2B 10 Paper 3 40 20% This document consists of 22 printed pages. 70  s.f.  formula Paper 2A

2 Section A Answer all the questions in this section. 1 A ball is released from rest above the ground. Fig. 1.1 shows the variation with time of the velocity of the ball. Fig. 1.1 (a) (i) State the gradient of the graph (with units) from t = 0 s to the time of the ball’s first impact with the ground. [1] (ii) Describe the motion of the ball from t = 0 s to the time the ball reaches its maximum height after its first impact with the ground. [2] (iii) Explain why areas X and Y are equal. [1]

3 (b) The ball is subsequently released from rest the same distance above the ground, but with significant air resistance. The ball does not reach its terminal velocity during its motion. (i) Sketch, on Fig. 1.1, the variation of the velocity of the ball with time from t = 0 s to the time of the ball’s first impact with the ground. [1] (ii) Explain, in terms of forces acting, why the velocity of the ball varies as sketched in (b)(i). [2]

4 2 Fig. 2.1 shows the position of a person’s teeth (comprising incisors and molars), and his masseter muscle used to move the lower jawbone. Fig. 2.1 Fig. 2.2 shows a simplified model of the lower jawbone of negligible mass. The model consists of two straight parts of length 7.0 cm and 4.0 cm, making an angle of 50° to each other. During one particular bite of a piece of food, a downward force of 45 N is applied on the incisors at the front of the lower jawbone, while an upward muscle force F is exerted by the masseter muscle at the back of the lower jawbone. Fig. 2.2 (a) The lower jawbone is in equilibrium. Determine the magnitude of the muscle force F applied by the masseter muscle. magnitude of muscle force F = [2]

5 (b) Hence, determine the magnitude and direction of the force applied on the pivot. magnitude of force on pivot = direction = [2] (c) Suggest, for the same moment created by the jaw bone, why the molars used for crushing hard food are found at the back, rather than the front of the jaw. [2] (d) Incisors are sharper than molars. Using concepts of pressure, suggest why incisors are used for cutting meat rather than molars for the same force exerted by incisors and molars. [2]

6 3 A hot steel rod is cooled by plunging it into cold water, as shown in Fig. 3.1. Fig. 3.1 (a) The steel rod has a mass of 2.0 kg and is initially at a temperature of 500 °C. It cools to 50 °C when placed in the water. The specific heat capacity of steel is 460 J / (kg °C). (i) State what is meant by specific heat capacity. [2] (ii) Calculate the energy transferred by heating from the steel rod to the water as it cools to 50 °C. Assume no energy is transferred to the surrounding air during this process. energy transferred = [2] (b) When the water and the steel rod are at a temperature of 50 °C, energy is subsequently transferred from the water to the air above it by a convection current. Describe how the convection current is produced in the air. [3]

7 4 Fig. 4.1 is a full-scale diagram that represents a sound wave of frequency 5.1 kHz in air. Sound waves are longitudinal waves. Fig. 4.1 (a) State what is meant by a longitudinal wave. [1] (b) (i) On Fig. 4.1, mark accurately with a cross, the position of one centre of compression labelled with the letter C, and of one centre of rarefaction labelled with the letter R. [2] (ii) Using the full-scale diagram, measure the wavelength of this sound wave. wavelength = [1] (iii) Calculate the speed of sound in air. speed of sound = [2] (c) Both sound and light are waves. Sound travels faster in glass than in air, but light travels faster in air than in glass. Explain why this is so. [2]

8 5 (a) The list below contains three components of the electromagnetic (EM) spectrum. infra-red radiation gamma rays visible light (i) Arrange the components in order of increasing wavelength. [1] (ii) State two properties that these components have in common. [2] (b) Satellites are used in the transmission of television signals, as shown in Fig. 5.1. Fig. 5.1 (i) State which component of the EM spectrum is used to transmit the television signal to the satellite. [1] (ii) State another component of the EM spectrum that is also used to transmit television signals, but without using satellites. [1] (iii) Suggest one advantage of using a satellite to transmit television signals. [1]

9 6 An object is placed 4.5 cm in front of a thin converging lens of unknown focal length as shown in Fig. 6.1. The image formed is the same size as the object and on the opposite side of the lens from the object. Fig. 6.1 (a) State what is meant by focal length. [1] (b) On Fig. 6.1, draw a ray diagram to determine the focal length of the lens. Show any necessary working below. focal length = [3] (c) Describe how one of the characteristics of the image changes during the following adjustments to the position of the object: (i) the object distance is decreased from 4.5 cm to 4.0 cm. [1] (ii) the object distance is decreased from 2.0 cm to 1.0 cm. [1]

10 7 A teacher carries out an experiment on radioactivity using the apparatus as shown in Fig. 7.1. Fig. 7.1 (not to scale) The count rate is a measurement of the count per minute. (a) (i) State the name of one type of radiation detector. [1] (ii) State one safety precaution the teacher must take when using a radioactive source. [1] (b) (i) State what is meant by background radiation. [1] (ii) The teacher measures the count