Bedok South 2024 Sec 4EXP PHY PRELIMS P2

[Turn Over BEDOK SOUTH SECONDARY SCHOOL PRELIMINARY EXAMINATION 2024 4EXP CANDIDATE NAME CLASS REGISTER NUMBER PHYSICS Paper 2 Structured and Free Response Candidates answer on the Question Paper. No Additional Materials are required. 6091/02 22 August 2024 1 hour 45 minutes READ THESE INSTRUCTIONS FIRST Write your class, index number and name on 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, 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. Setter: Ms Toh QM For Examiner’s Use Marks 80 This document consists of 24 printed pages.

2 Section A Answer all the questions. 1 Fig.1.1 shows a tube full of mercury placed upside down in a dish of mercury. A small piece of glass closes the open end of the tube. The piece of glass is removed and the level of mercury in the inverted tube falls, as shown in Fig. 1.2. (a) (i) Explain why the level of mercury in the tube falls. ………...…………………………………..………………………………………. ………...…………………………………..………………………………………. ………...…………………………………..………………………………………. ………...……………………………………………..………………………….[2] (ii) State what is found at point X in Fig. 1.2. ………...……………………………………………..………………………….[1]

3 [Turn Over (b) Describe how the tube of mercury in Fig. 1.2 is used to determine a value for the atmospheric pressure in pascals (Pa). You may draw on Fig. 1.2 to aid in your description. ………...…………………………………..………………………………………......… ………...…………………………………..………………………………………......… ………...…………………………………..………………………………………......… ………...……………………………………………..……………………………......[2] [Total: 5]

4 2 Fig. 2.1 shows a young boy lying on his back on the bottom of a swimming pool. He is holding his breath and his eyes are open. A red light is positioned on the ground at Q. At first the boy’s head is touching the pool wall. He notices that, as he slides away from the pool wall, his eye reaches a point P where he first sees the light at Q. Fig. 2.1 (a) On Fig. 2.1, draw the ray of light travelling from Q to P. Mark the critical angle for light in water and label it C. [2] (b) Explain why the boy is unable to see the red light at Q when his eye is closer to the pool wall than at point P. ………...…………………………………..………………………………………......… ………...…………………………………..………………………………………......… ………...…………………………………..………………………………………......… ………...……………………………………………..……………………………......[2] (c) The critical angle is 49°. Calculate the refractive index of water. refractive index = ......................................... [2] [Total: 6]

5 [Turn Over 3 A small, very brightly illuminated display is located at the back of a projector. The projector lens produces an image of the display on a white classroom wall. Fig. 3.1 shows the position and size of both the display and the image on the wall. R is a point on the display. Fig. 3.1 (a) State three characteristics of the image. .............................................................................................................................. ................................................................................…………………………......[1] (b) On Fig. 3.1, (i) draw two rays from R to the image, (ii) draw a vertical line representing the lens and label it L, and (iii) mark the position of a focal point F. [4] [Total: 5]

6 4 Fig. 4.1 shows a circuit that contains a direct current (d.c.) power supply, a light - dependent resistor (LDR), two fixed resistors, M and N, and two ammeters. The reading on ammeter 1 is 1.6 mA. Fig. 4.1 (a) Calculate the time taken for a charge of 7.2 C to pass through ammeter 1. time taken = ………………….. [2] (b) Some time later, the brightness of the light incident on the LDR decreases. (i) Explain what happens, if any, to the reading on ammeter 2. ..................................................................................................................... ..................................................................................................................... ..................................................................................................................... .................................................................................................................[2] (ii) Explain what happens to the time taken for a charge of 7.2 C to pass through ammeter 1. ..................................................................................................................... ..................................................................................................................... ..................................................................................................................... .................................................................................................................[2] [Total: 6]

7 [Turn Over 5 Fig. 5.1 shows the circuit with a 12 V battery, three resistors and two open switches, S1 and S2. YZ is a straight, horizontal section of connecting wire that lies between two magnets. Fig. 5.1 (a) Switch S1 is now closed while switch S2 remains open. (i) Calculate the current in YZ. current in YZ = ………………………. [2] (ii) Explain why YZ experiences a force. ………...…………………………………..……………………………………… ………...……………………………………………..…………………………[1] (iii) State and describe how the direction of the force on YZ is determined. ………...…………………………………..……………………………………… ………...…………………………………..……………………………………… ………...…………………………………..……………………………………… ………...……………………………………………..…………………………[2]

8 (b) Switch S2 is now closed too. Explain what happens, if any, to the force on YZ as switch S2 is closed. .............................................................................................................................. .............................................................................................................................. .............................................................................................................................. ................................................................................…………………………......[2] [Total: 7]

9 [Turn Over 6 Fig. 6.1 shows the coil of a loudspeaker attached to a cardboard cone. One pole of a stationary cylindrical magnet lies near to the coil. Fig. 6.1 There is an alternating current in the coil of the loudspeaker. A student hears the note produced. (a) (i) Explain why the cone of the loudspeaker vibrates. ...................................................................................................................... ...................................................................................................................... ...................................................................................................................... ..................................................................................................