HCI S3 Physics EOY 2020 P2

1 Hwa Chong Institution Examinations Secondary 3 Integrated Programme CANDIDATE NAME CLASS REGISTER NUMBER PHYSICS Paper 2 Theory October 2020 1 hr 45 mins Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your name, class and register 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. DO NOT WRITE IN ANY BARCODES Section A Answer all questions. Section B Answer all questions. Question 10 has a choice of parts to answer. 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 rather than correct answers. 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. This document consists of 19 printed pages and 1 blank page.

2 SECTION A (40 MARKS) Answer all the questions in this section. 1 Fig. 1.1 and 1.2 show the readings on a vernier caliper with the jaws closed and with a test tube clamped between its jaws respectively. Fig. 1.1 Fig. 1.2 (a) Write down the zero error of the vernier caliper. [1] (b) Determine the actual diameter of the test tube. [2] (c) Besides zero error, name a systematic error that could occur when conducting this measurement. [1] 0 1 0 10 5 3 4 0 10 5

3 2 Diamond is useful for industrial applications and jewellery. The cut of a diamond affects how light gets transmitted into the eye of the observer when light passes through diamond. The depth of its pavilion from its crown governs the path light will travel when it enters the diamond from the outside. A diamond that has a good cut is one that allows most light rays to exit from the top of the crown when light is shone from any angle around it. An incident ray of light is allowed to enter the surface of the diamond as shown in Fig. 2. The refractive index of diamond is 2.4 and its critical angle is approximately 25 . (a) Calculate the speed of light in diamond given the speed of light in air is 3.0  108 m s-1. [1] (b) Given the angle of incidence that light enters the diamond is 45 , find the angle of incidence, x, that the light ray hits surface AB. [2] (c) Complete the path of the light ray in Fig. 2 to show how it exits the top of the diamond. (Note: the diagram is not drawn to scale) [2] (d) The depth of the pavilion plays a pivotal role in how light gets reflected internally and thus how bright a diamond sparkles. With reference to Fig. 2, explain why a diamond with a shallower pavilion will not shine as brightly as one with a deeper pavilion. ..................................................................................................................................... ………………………………………………………………………………………………… …………………………………………………………………………………………….. [2] Crown Pavilion Fig. 2 Not drawn to scale

4 3 Fig. 3 shows a sharp image being formed on a screen placed in front of a thin converging lens. (a) Complete Fig. 3 to show how the ray diagram can be used to determine the position of the object. [3] (b) When a permanent marker is used to shade the upper half of the lens, the image on the screen looks different. Identify the difference and suggest a reason for the difference. ...………………………………………………………………………………………………. ...………………………………………………………………………………………………. ...…………………………………………………………………………………………..... [2] Screen Lens Image F F 2F 2F Fig. 3

5 4 Fig. 4 shows a 400 N weight supported by two strings, inclined at angles 30  and 50  to the vertical respectively. By drawing a scaled diagram, determine the tensions in both strings. State the scale used. [5] 400 N 30  50  T1 T2 W Fig. 4

6 5 Fig. 5.1 shows a ball placed at the top of a slope. A block is fixed rigidly to the lower end of the slope. The ball of mass 0.70 kg, initially at rest, is released from the top of the incline and the velocity of the ball rolling down the slope is found to vary with time as shown in the velocity-time graph as shown in Fig. 5.2. (a) Describe the motion of the ball during the following periods: (i) 0A …..........……………………………………………………………………………………….... …. ……….…………………………………………………………………………………... [1] (ii) AB ……….………………………………………………………………………………………….. ……….………………………………………………………………………………………….. ……………….………………………………………………………………………………….. ………………………………………………………………………………………………. [2] Fig. 5.1 Fig. 5.2

7 (b) Explain why the speed at B is less than the speed at A. …………………………………………………………………………………………………... ………………………………………………………………………………………………. [1] (c) Calculate the acceleration of the ball down the inclined slope. [2] (d) Sketch a displacement-time graph of the motion of the ball for t = 0 s to t = 2.20 s. The axes are drawn for you below. [2] s/m t/s 0 1.20 2.40

8 6 Table 6 shows a table of data of planetary radius and masses. The gravitational field strength, g, depends on the ma ss of the planet (in kg) and the radius of the planet (in m), given by the relationship: g = ( ) 2 11 planetofradius planetofmass1067.6  − (a) Using the above relationship and the information in Table 6, calculate the weight of a 65.0 kg astronaut on earth. [2] (b) The mass and weight of the astronaut is now measured on Neptune. (i) Suggest how the measurements on Neptune would be different from those measured on Earth. …….……..……………………………………………………………………………………… .…………………………………………………………………………………………...….. [1] (ii) Explain, with numerical evidence, your answers in 6(b)(i). …….……..……………………………………………………………………………………… …….……..……………………………………………………………………………………… .…………………………………………………………………………………………...….. [1] Planet Radius / 106 m Mass / 1025 kg Earth 6.38 0.597 Jupiter 71.5 190 Mars 3.40 0.0640 Mercury 2.44 0.0330 Neptune 24.8 10.2 Table 6

9 (c) A spacecraft travelled past Neptune and took several pictures. It is programmed to send signals of these pictures back to Earth and is detected by big-dish antenna on Earth as shown in Fig. 6. (i) Identify the component in the electromagnetic spectrum that is used to send these signals. ………………………………………