2023 CGS Phy Prelims P2

This paper consists of 19 printed pages (including the cover page). 3 CRESCENT GIRLS’ SCHOOL SECONDARY FOUR PRELIMINARY EXAMINATION PHYSICS 6091/02 Paper 2 28 Aug 2023 1 hr 45 min Class: Register No: Name: READ THESE INSTRUCTIONS FIRST Write your name, index number and class in the spaces provided at the top of this page and on all separate answer sheets used. Write in dark blue or black pen. You may use a soft pencil for any diagrams, graphs, tables or rough working. Do not use staples, paper clips, highlighters, glue or correction fluids. Section A (50 marks) Answer all questions. Section B (30 marks) Answer all questions. Question 11 has a choice of parts, answer either one. 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. For Examiner’s Use Section A /50 Section B /30 TOTAL

2 Crescent 23 6091 S4 SA2 Section A (50 marks) Answer all questions. Write your answers in the spaces provided in the question paper. 1. A vernier calipers is used to measure the diameter of a small cylinder. Fig. 1.1a shows a vernier calipers and Fig. 1.1b shows the main scale and vernier scale of the vernier caliper in detail. The reading for the diameter of the cylinder is 2.15 cm. (a) (i) Describe how Fig. 1.1b shows that the reading is 2.15 cm. ………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………… …………………………………………………………………………………………………………… [2] (ii) State one precaution taken to find an accurate value for the diameter of the cylinder. ………………………………………………………………………………………………………………… …………………………………………………………………………………………………………… [1] (b) The length of the cylinder is 0.026 m and its mass is 4.0 g. Calculate the density of the cylinder. density = ……………………… [3] cylinder Fig. 1.1a Fig. 1.1b

3 Crescent 23 6091 S4 SA2 2. Fig. 2 shows the velocity-time graph for the gymnast. A gymnast jumps off from a high bar from A, lands on a trampoline at B and is in contact with the trampoline between B and C. D is the highest position reached by the gymnast as she rises. Air resistance is negligible. Fig. 2 (a) Table. 2 shows the direction of motion of the gymnast and the direction of acceleration of the gymnast. Complete Table. 2. [2] direction of motion of gymnast direction of acceleration of gymnast during AB during CD Table. 2 (b) Using the information from Fig. 2, describe the motion of the gymnast between C and D. ………………………………………………………………………………………………………………… …………………………………………………………………………………………………………… [1] (c) State how Fig. 2 shows that the distance covered between A and B is larger than the distance covered between C and D. ………………………………………………………………………………………………………………… …………………………………………………………………………………………………………… [1] (d) Determine 1 the change in speed of the gymnast between B and C: ………………………. [1] 2 the change in velocity of the gymnast between B and C: ………….…………. [1] time/s velocity/ m/s 1 2 3 -6 10 A B C D

4 Crescent 23 6091 S4 SA2 3. Fig. 3 shows a section of the roller coaster track in Universal Studios at Sentosa. The total mass of the roller coaster and its passenger is 1000 kg. The speed of the roller coaster at A is 20 m/s. B and C are the bottom and top points of a vertical loop respectively. A is 30 m above B. The roller coaster travels 250 m from A to B and the speed is 22 m/s when it reaches B. (a) State what is meant by the Principle of Conservation of Energy. ………………………………………………………………………………………………………………… …………………………………………………………………………………………………………… [1] (b) Calculate the kinetic energy of the roller coaster at B. kinetic energy = ……………………… [2] (c) Calculate the work done against friction from A to B. work done = ……………………. [2] Fig. 3

5 Crescent 23 6091 S4 SA2 4. Fig. 4 shows a ray of light PQRS as it enters and leaves a semi-circular glass block. The speed of light in air is the same as the speed of light in a vacuum, which is 3.0 x 108 m/s. The refractive index of glass is 1.5. (a) Explain why there is no change in the direction of the ray as it enters the block at Q. [1] (b) Calculate the speed of light between Q and R. speed = …………………………. [2] (c) Another ray passes along TR. On Fig. 4, draw and label this ray as it leaves the block at R. [1] (d) A third ray passes along UR and some of the light emerges into the air at R along the surface of the block. (i) On Fig. 4, label the critical angle c. [1] (ii) The block is replaced by another block which has a higher refractive index. State and explain what happens to ray UR at R now. [3] Fig. 4

6 Crescent 23 6091 S4 SA2 5. Fig. 5 shows a negatively charged metallic sphere held with an insulated handle. The sphere is brought near an earthed metal plate attached to a galvanometer via a copper wire. (a) On Fig. 5, draw the electric field set up between the sphere and the metal plate. [2] (b) Explain what happens to the charges on the metal plate when the charged sphere is brought near the metal plate. [2] (c) Suggest one method to increase the momentary deflection of the galvanometer. [1] (d) The sphere is now replaced with an identical metal sphere that is positively charged and brought near the metal plate. State any changes to the deflection on the galvanometer. [1] Fig. 5

7 Crescent 23 6091 S4 SA2 6. Fig. 6 shows a light dependent resistor (LDR) and a battery of e.m.f 6.0 V connected in a circuit. When no light falls on the LDR, its resistance is 3.6 kΩ. In dim light, its resistance is 1.2 kΩ. The maximum resistance of the potential divider, AB, is 600 Ω. The slider X is at the midpoint of AB. (a) State the potential difference across AB. [1] (b) When no light falls on the LDR, calculate (i) the total resistance in the circuit, resistance = ………………………. [1] (ii) the reading on ammeter A. ammeter reading = ………………………. [1] (c) Determine the potential difference across the LDR when the entire circuit is placed under dim light. potential difference = ……………………….. [2] Fig. 6 6.0 V 1.2 k

8 Crescent 23 6091 S4 SA2 (d) State and explain what happens to the voltmeter reading when the slider X is shifted toward point A. [2] 7. Fig. 7.1 shows a coil of wire C connected to a switch and a strong battery. The coil of wire is wound round a hollow cylindrical tube G made of paper. When the switch is closed, the current in the solenoid creates a magnetic field. (a) A magnetic field passes through A and B. On Fig. 7.1, draw this magnetic field line both inside and outside the solenoid. Draw an arrow on the line to show the direction of the magnetic field. [1] Fig. 7.1

9 Crescent 23 6091 S4 SA2 (b) With the switch still closed, a compass is now placed at the right end of the coil as shown in Fig. 7.2. The North