NHHS 2025 PHY PRELIM P2 QP

This document consists of 21 printed pages. Name: _____________________________________ ( ) Class: Sec 4 / ( ) Subject : Physics Paper : 6091/02 Level : Secondary Four Date : 1 September 2025 Duration : 1 hour 45 minutes READ THESE INSTRUCTIONS FIRST Write your name, class and register number in the spaces at the top of this page. Write in dark blue or black pen. You may use HB pencil for any diagrams or graphs. Do not use staples, paper clips, highlighters, 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. NAN HUA HIGH SCHOOL PRELIMINARY EXAMINATION 2025 For Examiners’ Use Section A Section B Total

Nan Hua High School Preliminary Examination 2025 Physics 6091/2 Page 2 of 21 Section A Answer all the questions in this section. 1 (a) A 7.0 kg picture frame is being suspended from a nail by a string. The string forms two segments exerting tensions T1 and T2 as shown in the Fig. 1.1. The strings also make an angle of 35° and 60° with the vertical respectively. Fig. 1.1 In the space below, draw a vector diagram to determine the tensions T1 and T2. Specify the scale used. T1 = T2 = [4]

Nan Hua High School Preliminary Examination 2025 Physics 6091/2 Page 3 of 21 (b) (i) Explain what is meant by the precision of a measuring instrument. [1] (ii) Hence, state the precision of a digital caliper. [1] (c) Currently nuclear power provides approximately 9% of the world's electricity. This translates to about 2600 terawatt-hours (TWh) of electricity generated annually by nuclear reactors. Calculate the energy generated by nuclear reactors annually in joules. energy = ………………... [2]

Nan Hua High School Preliminary Examination 2025 Physics 6091/2 Page 4 of 21 2 (a) State the principle of moments. [1] (b) Fig. 2.1 shows a decoration that hangs by string from the ceiling in a toyshop. Four objects, P, Q, R and S hang by string from rods 1 and 3. These two rods hang by string from rod 2. The decoration is completely stationary and the rods are horizontal. The weights of the rods and the strings may be neglected. Fig. 2.1 (not to scale) Object P weighs 0.60 N and object Q weighs 0.16 N. (i) Calculate the value of the distance d on Fig. 2.1. d = [2] (ii) Determine the weight of object R and of object S. weight of R = weight of S = [2] (iii) Object P falls off. Using moments, state and explain what happens to rod 1 and rod 2. rod 1: rod 2: [2]

Nan Hua High School Preliminary Examination 2025 Physics 6091/2 Page 5 of 21 3 Fig. 3.1 shows a U-shaped tube, containing mercury, is used as a manometer to measure pressure from a cylinder of gas. Fig. 3.1 When one side of the cylinder is connected to an unknown gas A, the difference in mercury levels is 10.0 cm. (Density of mercury = 13 600 kg / m3, g = 10 m / s2) (a) If atmospheric pressure is 76 cm Hg, calculate, in units of Pascal, (i) the pressure difference between gas A and air, pressure difference = [2] (ii) the pressure of gas A. pressure of gas A = [2] (b) The setup in Fig. 3.1, which was on the surface of the Earth, is now transported to the top of a mountain with gas A still connected to the right of the manometer. State and explain the changes (if any) in the mercury levels in the tube. [2]

Nan Hua High School Preliminary Examination 2025 Physics 6091/2 Page 6 of 21 4 Fig. 4.1 shows a semi-circular glass prism with a light ray directed towards O, the midpoint between A and B. The refractive index of the glass prism is 1.8. Fig. 4.1 (a) Explain why there is no refraction when the light ray enters the glass prism at C. [1] (b) What is the maximum angle θ, such that the emergent ray will occur along the edge AB. maximum angle = [2] (c) Fig. 4.2 shows the same glass prism with another light ray directed towards O at the same angle θ. Fig. 4.2 (i) On Fig. 4.2, draw a possible path of the light ray as it enters and exits the glass prism. [1] (ii) Explain if total internal reflection will occur in Fig. 4.1 or Fig. 4.2 if angle θ can be varied. [1]

Nan Hua High School Preliminary Examination 2025 Physics 6091/2 Page 7 of 21 (d) Fig. 4.3 shows a simple optical fibre of the same glass material in Fig. 4.1. A light ray PQ enters the fibre and strikes the curved surface at an angle 60°. Complete the path of the light ray until it reaches the end surface labeled XY. Label all relevant angles values within the optical fibre. Fig. 4.3 (not to scale) [2]

Nan Hua High School Preliminary Examination 2025 Physics 6091/2 Page 8 of 21 5 In a tsunami created by an earthquake, it was observed that a ship took 20 min to move from its highest point to its lowest point. The distance between the highest point and the lowest point was 20 m. (a) (i) Define the period of a wave. [1] (ii) Determine the frequency of the tsunami wave. frequency = [2] (b) When the ship was at its highest point, another ship that was 300 km away was also at its highest point. There were two crests between the two ships. Fig. 5.1 shows the displacement-distance graph of the wave. Fig. 5.1 (i) Determine the magnitudes of X and Y. magnitude of X = [1] magnitude of Y = [1]

Nan Hua High School Preliminary Examination 2025 Physics 6091/2 Page 9 of 21 (ii) Show that the speed of the wave is about 42 m / s . [1] (iii) The tsunami wave was detected at 0800 hrs and the distance between the tsunami wave and the shore was 200 km. Determine the time that the tsunami wave will reach the shore. time of arrival = [2] (c) Describe the motion of the ship as the first waves arrive at the ship. [1]

Nan Hua High School Preliminary Examination 2025 Physics 6091/2 Page 10 of 21 6 Fig. 6.1 shows a light plastic sphere coated with silver conductive paint being suspended by a length of insulating thread. Fig. 6.1 (a) A positively charged rod is placed near to the sphere as shown in Fig 6.2. Fig. 6.2 (i) On Fig. 6.2, 1. draw the charges on the sphere, [1] 2. draw the electric field set up between the charged rod and the sphere. [1] (ii) The rod touches the sphere for a moment before being separ