Shun Lee Catholic Secondary School First Examination (2015-2016) Question-Answer Book Level : Secondary 3 Name : ___________________ S 3 ____ ( ) Subject : Science (Physics) Score Time allowed : 30 minutes Full mark : 30 marks / 30 Instructions – Please read carefully before the examination starts. 1. When told to open this paper, you should check that all the questions are there. Look for the words ‘END OF PAPER’ after the last question. 2. After the announcement of the start of the examination, you should first write your name, class and class number in the space provided on this page. All information should be included. Otherwise, mark(s) will be deducted. 3. This paper must be answered in English. 4. This paper consists of TWO sections, Section A and Section B. Section A (Multiple Choice Questions) carries 10 marks and Section B (Short Questions) carries 20 marks. 5. Answer ALL questions in each section. Write your answers in the spaces provided in this Question-Answer Book. Page 1 of 9 Section A 1. Multiple Choice Questions (1 mark each) The nearest star Proxima Centauri is 4.3 light years from us. Given the speed of light is 3 108 ms-1, find the distance of Proxima Centauri from the Earth in metres (m). A. B. C. D. 1.44 1011 m 9.46 1015 m 4.07 1016 m <ANS> 1.33 1019 m ANS: _______ 2. The wavelength of visible light, from red light to violet light, ranges from A. 400 nm to 700 nm. <ANS> B. 700 nm to 1400 nm. C. 100 nm to 400 nm. D. 1000 nm to 1400 nm. ANS: _______ 3. Susan and Peter stand in front of a big mirror at different distances as shown. How far away is the image of Peter from Susan? 2m 4m A. B. C. D. 2m 4m 6m <ANS> 8m ANS: _______ Page 2 of 9 4. Susan sees the image of a wall picture behind her through the mirror. The image is formed 12m away from her as shown. If the height of the picture is 5m, estimate is the MINIMUM length of the mirror so that she can see the whole image of the picture? 12 m 5m Mirror 4m A. B. C. D. Image of picture behind Susan 0.42 m 1.67 m <ANS> 2.5 m 5m ANS: _______ 5. Which of the following may form a clear image? (1) Diffuse reflection (2) Refraction by a tank of water (3) Refraction by convex lens A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only <ANS> ANS: _______ 6. Which of the following descriptions about the refraction of light when light travels from glass to air is INCORRECT? A. Light travels faster in glass. <ANS> B. The light ray bends away from normal. C. The refracted angle may equal 90. D. Total internal reflection may occur when incident angle is large enough. ANS: _______ Page 3 of 9 7. AIR Refer to the figure on the right, calculate the refractive index of the glass block. A. B. C. D. 40 0.653 0.742 1.35 1.53 <ANS> 60 GLASS ANS: _______ 8. Calculate the critical angle of diamond (i.e. diamond-air interface). Given that the refractive index of diamond is 2.42. A. 23.7 B. 24.4 <ANS> C. 65.6 D. 22.5 ANS: _______ 9. Which of the following is/are advantage(s) of using MIRRORS to construct a periscope instead of using PRISMS? (1) the image is brighter (2) the image is sharper (3) the periscope is lighter (4) the periscope is cheaper A. (1) and (2) only B. (3) and (4) only <ANS> C. (1) and (3) only D. (2) and (4) only ANS: _______ Page 4 of 9 10. Which of the followings are applications of total internal reflection ? (1) optical fibre (2) mirage (3) rainbow A. (1) and (2) only B. (2) and (3) only C. (1) and (3) only D. (1), (2) and (3) <ANS> ANS: _______ Short Questions: 11. Draw the image of the following objects formed by a plane mirror. (2 marks) (a) (b) Page 5 of 9 12. To anyone on the ground, a swimming pool looks shallower than it really is. Complete the following ray diagram to explain. Hint: You should label the image of the bottom of the pool in your diagram. (2 marks) A pool of water 13. A stick looks bent due to light refraction when partly immersed in water as shown. Complete a ray diagram below to explain why it happens. (3 marks) A stick partly immersed in water Page 6 of 9 14. A semi-circular glass block and a semi-circular water tank are placed side by side as shown below. What are the angles of incidence and angle of refraction ? (2 marks) Angle in water: ________________ Angle in glass: _________________ Semi-circular water tank Semi-circular glass block 15. Refer to the last question. Calculate the refractive index of the glass block. Given refractive index of water water = 1.33. (2 marks) Page 7 of 9 16. Refer to the Question 14 again. If the incident angle further increases, what would happen to the brightness of refracted ray? What about the brightness of reflected ray? (2 marks) 17. A periscope is constructed using mirrors as shown. Draw the two marked light rays from the object to the observer eye. (1 mark) Object Fig. 17 18. Fig.18 In Fig.18, draw two prisms to form a periscope. (1 mark) Page 8 of 9 19. A real image is formed by a convex lens of focal length 4 cm. The object is placed 10 cm from the lens. Complete the ray diagram below and locate and label the image. (3 marks) 20. For the image formed in Q19 above, what is the nature and magnification of the image? (2 marks) - END - GOOD LUCK ! Page 9 of 9