DIRECTORATE FOR QUALITY AND STANDARDS IN EDUCATION Department for Curriculum Management Educational Assessment Unit Track 3 Annual Examinations for Secondary Schools 2016 FORM 4 PHYSICS TIME: 1h 30min Name: Class: INFORMATION FOR CANDIDATES Where necessary take acceleration due to gravity g to be 10 m/s 2. The use of a calculator is allowed. The number of marks for each question is given in brackets at the end of each question. You may find these equations useful. Force F = m a W = m g Motion Electricity Waves total distance (u + v) t Average Speed = total time s = s = ut + 1 2 2 at2 v = u + at v 2 = u 2 + 2as Momentum = m v Q = I t V = I R E = Q V R L/A R TOTAL = R 1 + R 2 + R 3 real depth η = apparent depth v = f λ f = 1 T E = I V t 1 = 1 + 1 R TOTAL R 1 R 2 speed of light in air η = speed of light in medium magnification = h i image height = h o object height Others Area of triangle = 1 2 bh Area of Trapezium = 1 (a + b)h 2 INSTRUCTIONS TO CANDIDATES Use blue or black ink. Pencil should be used for diagrams only. Read each question carefully and make sure that you know what you have to do before starting your answer. Answer ALL questions. All working must be shown. This document consists of 10 printed pages. For Examiner s Use Only Question Max Mark 1 8 2 8 3 8 4 8 5 8 6 15 7 15 8 15 Written 85 Practical 15 Total 100 Physics Form 4 Secondary Track 3 2016 Page 1 of 10
SECTION A Each question carries 8 marks. This section carries 40 marks of the total marks for this paper. 1. Figure 1 shows a sound wave travelling through air from a loudspeaker to a human ear. Figure 1 a) On the diagram above, label a compression with a C and a rarefaction with an R. [2] b) Indicate, on the diagram, one complete wavelength using its correct symbol. [1] c) How many complete waves are shown in the diagram? _[1] d) The distance between the loudspeaker and the ear is 16.5 m. It takes 0.05 seconds for a sound wave to reach the ear. Calculate the speed of sound in air. e) Calculate the frequency in Hz of this sound wave. 2. A two euro coin rests at the bottom of a pool of water, as shown in Figure 2. Figure 2 a) On the diagram, draw the path followed by a ray of light from the coin to the eye. [2] b) Underline: The speed of the ray of light as it emerges into the air (increases, decreases, remains the same). The image of the coin is (real, virtual). [2] Page 2 of 10 Physics Form 4 Secondary Track 3 2016
c) Give ONE reason why the ray of light bends as it emerges from the water. d) The coin appears at a depth of 1.5 m when viewed from above. Given that the refractive index of water is 1.33, calculate the real depth of the pool of water. 3. Police use radar guns to determine the speed of cars along the road. The microwave beam emitted by the radar gun gets reflected off the moving car and the difference between the outgoing and the incoming frequencies of the microwaves is used to determine the speed of the car. a) Is it possible for a driver to see and avoid the microwave beam? Why? b) State ONE property that electromagnetic waves have in common. _[1] c) A radar speed trap shows a change of frequency of 3000 Hz when used to measure the speed of a car. Use the graph to find the speed of the car. [1] d) If the speed limit is 60 km/h, will the police issue a ticket to this car? Show your calculations. Figure 3 e) If the radar gun operates at a frequency of 10700 MHz, calculate the wavelength of the waves used. The speed of light is 300 000 000 m/s. Physics Form 4 Secondary Track 3 2016 Page 3 of 10
4. A car is driven along a straight road. The graph shows how the velocity of the car changes from the moment the driver sees a very slow-moving queue of traffic ahead. A B C Figure 4 a) Using the graph or otherwise, calculate the deceleration of the car between points A and B. b) Calculate the distance covered by the car in the first 10 seconds. c) Calculate the average speed of the car and draw a line to indicate this speed on the graph. d) After the 10 seconds shown on the graph, the driver accelerates and reaches a speed of 18 m/s in a distance of 200 m. Calculate the time it took the car to cover this distance. Page 4 of 10 Physics Form 4 Secondary Track 3 2016
5. Julia was investigating current flow through a lamp. Figure 5 a) In the space provided, draw the circuit diagram for this setup using the correct circuit symbols. [2] b) The resistance of the lamp when brightly lit is 15. Calculate the current in Amps flowing through the lamp if the potential difference measured by the voltmeter is 1.5 V. c) Another lamp that has double the resistance of the first lamp is connected in parallel to the first lamp. Calculate the total resistance of the two lamps. d) Underline: The voltmeter reading will (increase, decrease, remain the same) when the second lamp is connected in parallel to the first lamp. [1] e) Explain why a lamp does not obey Ohm s law. _[1] Physics Form 4 Secondary Track 3 2016 Page 5 of 10
SECTION B Each question carries 15 marks. This section carries 45 marks of the total marks for this paper. 6. Julia was investigating how the current through a thermistor changes with the voltage across it. She sets up the apparatus as shown in Figure 6. a) The multimeter labelled X is being used as an and is connected in. [2] X Y b) Name another circuit component that Julia needs to change the voltage across the thermistor. [1] Figure 6 c) Name ONE precaution she must take to perform a reliable experiment. _[1] d) Describe briefly how she should carry out this experiment. _[3] e) During the experiment the data was collected in the following table. Voltage / V 0.00 1.00 2.00 3.00 4.00 5.00 6.00 Current /A 0.00 0.20 0.40 0.70 1.10 1.70 2.80 Plot a graph of Current on the y-axis against Voltage on the x-axis. [5] f) Use the graph to find the current flowing through the thermistor when the voltage across it is 3.50 V. _[1] g) From the graph, does the thermistor obey Ohm s law? Give a reason for your answer. _[1] h) How does the resistance of the thermistor change with increasing voltage? _[1] Page 6 of 10 Physics Form 4 Secondary Track 3 2016
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7. a) Peter was driving home after a very long day of work. He spots a hedgehog crossing the road, applies the brakes, swerves his car and collides head-on into a rubble wall. His car was moving at 15 m/s when it came to a complete stop on impact with the wall. Figure 7 i) Peter is not wearing his seatbelt and he hits the windscreen on impact. Which of Newton s Laws explains the forward movement of Peter on impact? State this law. ii) Name ONE other safety measure that is designed in cars to minimize injury to drivers on collision. [1] iii) The car came to a complete stop in 1.2 seconds. Calculate the deceleration of the car. iv) If the total mass of Peter and his car is 900 kg, calculate the force of impact that acted on the car. v) Suppose that Peter saw the hedgehog from a distance of 100 m and that his thinking time is 0.5 seconds. Calculate the braking distance that could have been available for Peter to stop the car. vi) Calculate the deceleration that would be needed to stop the car just next to the hedgehog. Page 8 of 10 Physics Form 4 Secondary Track 3 2016
Figure 8 b) An empty train cargo wagon of mass 10,000 kg is released from the engine and moves with a velocity of 4 m/s towards a stationary wagon of mass 30,000 kg. After collision the two wagons join together. i) Calculate the total momentum of the two wagons before collision. ii) Calculate the velocity of the two wagons after collision. 8. Elizabeth and Neville are investigating the properties of a lens and a prism. a) Elizabeth is given a converging lens. Describe briefly how she could use a distant object to find an approximate value for the focal length of the lens. _[3] Physics Form 4 Secondary Track 3 2016 Page 9 of 10
b) Elizabeth uses this lens to obtain a sharp image on a screen of an object 8 cm high that is placed in front of the lens. Scale: 1 square = 2 cm Figure 9 i) On the diagram above, mark the principal focus F of the lens. [1] ii) Calculate the focal length of the lens. iii) State TWO properties of the image formed on the screen. iv) Calculate magnification of lens. c) Neville shines a ray of white light through a prism. i) Complete the ray diagram to show how the red and blue rays of the spectrum form on the screen. Label clearly. [2] ii) What is this effect called? Glass Prism White Light Screen Figure 10 [1] iii) Name ONE example where this happens in nature. [1] iv) Which colour travels fastest inside the glass prism? [1] Page 10 of 10 Physics Form 4 Secondary Track 3 2016