Republic of Somaliland. Somaliland National Examination Board. Form Four. Physics Examination. June 2009 TIME 2 HOURS

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1 Name..... Total Score School... Roll No... Republic of Somaliland Form Four Physics Examination June 2009 TIME 2 HOURS Plus 10 minutes for reading through the paper Total time 2 Hours and 10 Minutes INSTRUCTIONS TO CANDIDATES This paper consists of 20 printed pages. Count them now. Inform the invigilator if there are any pages missing. PART 1: 20 Multiple Choice Questions 20 Marks PART 2: 7 Structured Questions 70 Marks PART 3: 1 Extended Question 10 Marks TOTAL 100 Marks Answer ALL questions in Part 1 and 2 and One question from part 3. All answers must be written on this paper in the spaces provided immediately after each question. Only write on this exam paper.

2 Use this page for rough work. It will NOT be marked

3 PART 1: ( 20 QUESTIONS): Answer All questions in this section ( 20 marks) Circle the correct answer. 1 The SI unit of length is mm km m cm 2. The mass of a body is the amount of matter in the body the volume the body occupies the product of its density and volume its weight at sea level 3. Which of the following is NOT a vector quantity? Force Energy Acceleration Momentum 4. Hooke s law states that. extension is directly proportional to the applied force. clockwise moments equal to anticlockwise moments. for every action there is an equal and opposite reaction. angle of incidence over the angle of refraction is a constant 3

4 5. A body floating in oil displaces its own.... volume of oil weight of oil surface area of oil depth of oil 6. Which of the following statements does NOT fit the kinetic theory of matter? Matter is made up of small particles called molecules The molecules are in constant motion or vibration The molecules of a solid expand when heated the higher the temperature, the faster the molecules move or vibrate 7. Water drops from a dripping tap are round. This is because. the molecules of water are round. water crystals are round. molecular attraction causes the round shape. atmospheric pressure causes the drop to be round 8. Specific latent heat is defined as. heat required to change water into steam. heat required to melt ice. heat exchange when the state of a unit mass of a substance changes without a temperature change. heat taken in or given out when the state of a substance changes 9. The inner surface of a vacuum flask is silvered to make it a bad absorber and bad conductor of heat bad absorber and good radiator of heat bad absorber and bad radiator of radiant heat good absorber and bad radiator of heat. 4

5 10. Charges arise because. protons move from one article to the other. electrons move from one article to the other. neutrons move from one article to the other. both neutrons and protons move together 11. Carbon brushes in an electric motor are used to. increase efficiency. brush the commutator. reverse the current. decrease resistance 12. A direct current flows from A to B. How is the current carried? Electrons move from A to B Electrons move from B to A Atoms move from A to B Atoms move from B to A 13. If an electrical appliance becomes live, the appliance stops working and is safe to touch continues working and is safe to touch continues working and is dangerous to touch is safe to touch because of the fuse. 14. Correction of short sight in the eye is by a converging lens placed infront of the eye a diverging lens placed infront of the eye moving away from near objects using binoculars 5

6 15. The image formed on the film of a simple camera is real, inverted, and diminished virtual, upright and diminished virtual, upright and magnified real, inverted and magnified 16. Cooling always accompanies evaporation because the air molecules cool the liquid surface the more energetic molecules leave the liquid there are fewer liquid molecules left in the liquid the escaped molecules return to the liquid 17. A train of 10,000 kg mass is hauled by an engine of 40,000 N. What is the acceleration of the train? 4m/s2 2m/s2 0.4m/s2 0.5m/s2 18. Water can boil at 101 0C if it is heated quickly it is purified salt is added sand is added 19. A mirage is formed due to refraction dispersion reflection scattering 6

7 20. Normal healthy body temperature is 20 0C C 37 0C 68 0C 7

8 SECTION B: ANSWER ALL QUESTIONS. Write your answers in the given spaces QUESTION ONE ( 9 marks) A lighted electric lamp is placed between two glass flasks containing air. One flask is painted silver, the other is black. There is coloured water in the tube and the levels of water are same or identical before heating commences. a) Name the processes by which heat passes through the glass of the lamp.. ( 1 mark) i passes from the outer surface of the lamp to the flasks. ( 1 mark) b) After a time it is noticed that the liquid level falls in the left hand and rises in the right hand tube. Which surface is a better absorber of heat? i ( 1 mark) What has happened to the pressure of the air in the black bulb?..( 2 mark) ii What has happened to the pressure of the air in the silvered bulb?.( 2 mark) iv) what can you say about the speed of movement of the molecules in the two bulbs? ( 2 mark) 8

9 QUESTION TWO ( 10 marks) The diagram below represents an electric bell. a). Name the parts; C (1) i D (1) ii E...(1) b). Identify a material suitable for E. (1) i Explain why the material is suitable for the electric bell.. (2) c). Explain how the bell works..(2) i. State two changes which can be made to E to increase its magnetism. (2) 9

10 QUESTION THREE ( 11 marks) Three identical lamps L1, L2, and L3, of resistance 10 Ω are connected to a 6 V cell of negligible resistance as shown in the figure below. 6V I2 L2 L1 X I1 Z Y I3 L3 Calculate the a) combined resistance of lamps L2 and L3. b) ( 3 mark) total resistance of the circuit c) ( 2 mark) current I1 ( 2 mark) 10

11 d) potential difference across XY.. ( 2 mark) e) current I3 ( 2 mark) QUESTION FOUR ( 10 marks) a). Define pressure i ( 1 mark) State the SI unit of pressure ( 1 mark) ii Explain why it is easier to cut meat with a sharp knife than with a blunt one (1mark) 11

b). The diagram below shows a simplified form of a hydraulic press. A force of 15N is 2 2 exerted on the small piston of area 0.025 m. The large piston has an area of 0.5m.

12 b). The diagram below shows a simplified form of a hydraulic press. A force of 15N is 2 2 exerted on the small piston of area m. The large piston has an area of 0.5m. Load 15 N Small piston Large piston What liquid is used by the hydraulic press? ( 1 mark) i State one property of the liquid that makes it suitable as the hydraulic fluid. c) ( 1 mark) Calculate the pressure exerted on the liquid by the small piston.. (2 mark) i pressure on the large piston ii (1 mark) force exerted by the large piston on the load. 12 ( 2mark)

QUESTION FIVE ( 10 marks) a) State two applications of electrostatics in everyday life...(1) i..(1) b) Explain why a glass window when wiped with a dry cloth on a dry day soon becomes dusty.

13 QUESTION FIVE ( 10 marks) a) State two applications of electrostatics in everyday life...(1) i..(1) b) Explain why a glass window when wiped with a dry cloth on a dry day soon becomes dusty....(1) c) During thunderstorm, Halima sees the flash of lightning followed by the thunder. Explain why (1) i Halima standing 1.0 km from the storm hears a sound of thunder 3 seconds after she sees a flash of lightning. Calculate the speed of sound in air ( 2 ) d) Daud stands some distance away from a cliff in Gabiley. He gives a shout and hears his echo 4 seconds later. How far is he from the cliff?.. (2) i Write down any two uses of echoes. (2) 13

14 ESTION SIX ( 10 marks) a). State the laws of reflection (2) b) A beam of white light passes through a triangular prism onto a white screen as shown below. The following colours are seen on the screen: yellow, red, green, orange, blue, indigo, and violet. Write down the colours as they appear on the screen from top to bottom on the diagram. c) (3 marks) Explain what would happen if a red filter is placed in the path of the white light. d) (2) Calculate the position and nature of the image formed by a convex lens of focal length 15 cm, of an object placed 20 cm from the lens...( 3) 14

15 QUESTION SEVEN (10 marks) a) Define and state the SI units of work (1) i power (1) b) A thin girl ( and a plump girl ( ran up a flight of steps as shown. Calculate the work done by girl A and B. Work by girl A (2) Work by girl B (1) 15

16 .c) If they both run up the steps in 5 seconds, Calculate the power developed by Girl A and B Power by girl A (2) Power by girl B (1).d) Who is more powerful? Why? (2 ) 16

17 PART 3: EXTENDED QUESTION ( 10 MARKS): Answer only ONE Question. Either answer question 1 OR question 2. QUESTION ONE a) The diagram shows parts of the electromagnetic spectrum in order. Some parts have been named. Radio waves P Visible light Q x-rays Write down the name of part P ( 1 mark) i Write down the name of part Q ( 1 mark) ii Look at the diagram. Which part of the spectrum has the shortest wavelength ( 1 mark) b) Use the following words to complete the following sentences infra-red, microwaves, radio waves, ultra-violet, visible light. Food can be cooked using. i Thermometers can detect ii Photographs taken with ordinary camera use iv) Skin cancer can be caused by ( 2 mark) 17

c) A Hargeisa hospital uses X-ray machines to take photographs of broken bones. A sheet of film is placed under the broken bone. The X-ray machine is turned on.

18 c) A Hargeisa hospital uses X-ray machines to take photographs of broken bones. A sheet of film is placed under the broken bone. The X-ray machine is turned on. An image of the broken bone is produced on the film. a) X-rays are dangerous. How does the X-ray operator protect himself from them? ( 2 mark) b) Explain how X-rays produce an image of the bone on the film.. ( 3 mark) QUESTION TWO a) Define velocity.. 18 ( 1 mark)

19 i acceleration ( 1 mark) b) A car runs at a constant speed of 15 m/s for 300 seconds and then accelerates uniformly to a speed of 25 m/s. This speed is maintained foe 300 seconds before the car is brought to rest with uniform deceleration in 30 seconds. Draw a velocity-time graph to represent the journey described above. ( 3 mark) From the graph find: the acceleration while the velocity changes from 15 m/s to 25m/s 19 ( 2 mark)

20 i the total distance traveled in the time described ( 2 mark) ii the average speed over the time described. ( 1 mark) END 20

Coimisiún na Scrúduithe Stáit State Examinations Commission

2014. M35 Coimisiún na Scrúduithe Stáit State Examinations Commission LEAVING CERTIFICATE EXAMINATION, 2014 PHYSICS ORDINARY LEVEL MONDAY, 16 JUNE MORNING, 9:30 TO 12:30 Answer three questions from Section