Physical Science Paper 1 SECTION A QUESTION 1: ONE-WORD/TERM ITEMS Give ONE word/term for EACH of the following descriptions. Write only the word/term next to the question number (1.1 1.5). 1.1 Characteristic of matter that resists any changes to its state of rest or movement. (1) 1.2 The pattern observed on a screen when light from two different sources interact. (1) 1.3 The energy that a battery uses to overcome its internal resistance. (1) 1.4 The type of spectrum observed when white light is dispersed by a glass prism. (1) 1.5 The non-conducting material that separates the plates of a capacitor. (1) [5] QUESTION 2: MULTIPLE-CHOICE QUESTIONS Four possible answers are provided for each of the following questions. Choose the correct answer and write down the letter that corresponds to your answer. (Each question has ONE correct answer). 2.1 An athlete accelerates at the beginning of a race by pushing his feet firmly against the starting blocks with a force F. The magnitude of the force with which the starting blocks push back on the athlete s feet is A zero B greater than F C less than F D equal to F 2.2 A ball with a mass of 1 kg (travelling towards the right) strikes a wall at right angles with a velocity of 2 m.s -1. It bounces back with a velocity of 1.5 m.s -1. The impulse of the ball (in kg.m.s -1 ) is: A 0.5 to the right B 0.5 to the left C 3.5 to the right D 3.5 to the left. 2.3 The kinetic energy of a moving object will increase most when its A mass is doubled B mass is halved C velocity is doubled D velocity is halved. 2.4 The following graph shows the frequency (f), as observed by a stationery listener, of a moving sound source, against time (t). f t 0 t At time t 0 : A the source began to slow down B the source began to move away from the listener. C the loudness of the source increased D the source began moving towards the listener. Copyright reserved Please turn over 1
2.5 Monochromatic blue light is shone through a single narrow slit, and the diffracted light is observed on a screen. If the blue light is replaced by monochromatic green light, while the width of the slit remains constant, then A alternating green and black bands, of equal length, will be observed B a broad central band, larger than that of the red light, will be observed C a broad central band, equal to that of the red light, will be observed D a broad central band, smaller than that of the red light, will be observed. 2.6 Atomic spectra provide evidence that: A light has a wave nature B electrons exist in fixed energy levels in atoms of an element, but can transit to higher or lower energy levels C the nuclei of atoms can be split under the action of light D light has a dual nature. 2.7 The leaves of a charged zinc electroscope will collapse under the action of blue light. This happens because: A blue light has the ability to remove electrons from the zinc surface B blue light has the ability to remove protons from the zinc surface C blue light has the ability to add electrons to the zinc surface D blue light has the ability to add protons to the zinc surface. 2.8 Which of the following magnitudes must be decreased in order to increase the electrical field intensity between two oppositely charged, parallel plates? A The charge on each plate B The distance between the plates C The potential difference between the plates D The area of each plate. 2.9 Two metal plates, each with an area of 2 cm 2, are 3 cm apart. If the potential difference across the plates is doubled and the distance apart is increased to 6 cm, then the maximum charge that can be stored on the plates will... A. be halved B. b e doubled C. remain the same D. quadruple. 2.10 Which SI-unit measures the rate of flow of electrical charge in a circuit? A Watt B Coulomb C Volt D Ampere. (10x2=20) [25] SECTION B QUESTION 3 A hot air balloon is rising vertically upwards with a constant velocity of 7 m.s -1 when one of the passengers accidentally drops a camera over the edge. The camera reaches the ground after 8 seconds. Below is a graph representing the motion of the camera from the moment it is dropped until it reaches the ground. Ignore the effects of air friction. Copyright reserved Please turn over 2
3.1 What is the initial velocity (v i ) of the camera relative to the ground? (1) 3.2 What is the value of the slope of the graph? Explain. (2) 3.3 Use the graph to calculate time t 1 shown on the graph. (3) 3.4 After how many seconds is the camera a maximum distance away from the ground? (1) 3.5 Write an equation for the straight line graph in terms of v and Δt. (3) 3.6 Calculate the magnitude of the velocity with which the camera reaches the ground after 8 seconds. (2) 3.7 Draw a position-time graph for the motion of the camera for the 8 s of its fall. Use the ground as the zero position. (3) [15] QUESTION 4 After taking a catch in a cricket match, AB de Villiers throws the ball vertically upwards so that it rises to a height of 14.45 m above the point from which the ball is thrown. The ball has a mass of 130 g. Ignore air friction. Determine: 4.1 the speed with which the ball left his hand. (4) 4.2 the impulse exerted by the hand on the ball when it was thrown upwards. (3) 4.3 the impulse exerted by the ball on the hand. (2) 4.4 the time that the ball is in the air. (4) [13] QUESTION 5 A rubble-carrying car in a mine has a total mass of 7 000 kg. It is being hauled up an incline to the surface when the cable snaps and the cart hurtles back down the frictionless incline. At the bottom of the incline the car collides with a row of four stationary, empty cars, each of mass 1 500 kg. The five cars automatically couple together and move off at a speed of 4 m.s -1. 5.1 Name a conservation law which can be used to determine the speed of the loaded car just before impact. (1) 5.2 Calculate the speed of the loaded car just before impact. (4) 5.3 Calculate the kinetic energy of the car just before impact. (3) Copyright reserved Please turn over 3
5.4 Is the collision elastic? Justify your answer by means of a calculation. (4) 5.5 Calculate the maximum vertical height of the car as it moves along the incline. (3) [15] QUESTION 6 6.1 In 1801 Young carried out his famous double slit experiment. a) What was his hypothesis? (2) b) What result did he obtain from his experiment and what conclusion did he reach from this? (2) c) Explain whether we, in the 21 st century, regard Young s theory of light as complete. (2) 6.2 The first order line of 520 nm light falling on a diffraction grating is observed at an angle of 18. What is the slit size? (5) [11] Copyright reserved Please turn over 4
QUESTION 7 7.1 A stationary listener perceives the sound from an airplane to be 800 Hz. However, the pitch of the sound emitted by the plane was actually 1 000 Hz. This result could only be due to a Doppler effect. What was the relative velocity of the plane as observed by the listener? Take the speed of sound in air to be 340 m.s -1. (6) 7.2 A whip produces a very loud crack in the hands of a skilled cowboy. Explain where the sound comes from. (3) [9] QUESTION 8 8.1 A current-carrying conductor PT is placed between the poles of a magnet as shown below: 8.1.1 Name the rule used to predict which way the conductor will move when the switch is closed. (1) 8.1.2 In which direction will the conductor move when the switch is closed? (1) 8.1.3 Name two ways to increase the force on the conductor. (2) 8.1.4 Name the device used to ensure continuous rotational motion in the above set up. (1) 8.2 In South Africa, electricity is supplied at 50 Hz and 220 V AC. Determine the peak voltage of this supply. (3) [7] QUESTION 9 Two identical small metal spheres, P and Q, each with a mass of 1 g, are placed on two insulated stands, 20 mm apart. The charge on P is +3 x 10-11 C and the charge on Q is -2 x -11 10 C. 9.1 Draw the electric field pattern between P and Q. (3) 9.2 Calculate the electrostatic force of attraction between the two spheres. (4) 9.3 The two spheres now make contact, exchange charge, and return to their original positions. Is the electrostatic force after contact a force of attraction or repulsion? (1) [8] QUESTION 10 Each plate of a parallel plate capacitor has an area of 40 cm 2. The plates are 1 cm apart. The capacitor is connected to a 12 V DC supply. 10.1 Calculate the magnitude of the charge on each plate. (6) Copyright reserved Please turn over 5
10.2 By what factor will the charge calculated in QUESTION 10.1 change if the area of each parallel plate is changed to 20 cm 2? Explain your answer in terms of physics principles and the charge stored in the capacitor. (NO calculations needed). (3) 10.3 What is the net charge on the capacitor? (1) [10] QUESTION 11 A battery of emf 20 V and internal resistance r is connected in a circuit as in the diagram. (R 1 and R 2 are identical resistors) When the switch S is open a current of 4 A is recorded on the ammeter and the reading on the voltmeter is 16 V. 11.1 Determine the value of R 1 and R 2. (6) 11.2 Calculate the internal resistance r. (3) 11.3 Calculate the reading on the ammeter when the switch S is closed. (5) 11.4 Would the reading on the voltmeter increase, decrease or remain the same when S is closed? Explain your answer without doing any further calculations. (4) 11.5 Determine the amount of heat released in half an hour by resistor R 1 when the switch is open. (4) [22] QUESTION 12 12.1. A learner wants to determine the relationship between the frequency (f) of light striking a metal surface, and the kinetic energy (K) of the emitted electrons. She shines red, green and blue light on the metal, and is able to measure the velocity of electrons as they leave the metal surface. 12.1.1 Identify the independent variable in this investigation. (1) 12.1.2 Why does she use light of different colours? (1) 12.1.3 Why does she measure the velocity of the emitted electrons? (1) The learner obtains the following average results after taking the reading several times. Colour Frequency (x 10 14 Hz) Kinetic energy of emitted electron ( x 10-19 J) Red 4.30 0.20 Green 5.60 1.10 Blue 5.70 1.20 Copyright reserved Please turn over 6
12.1.4 Use the results to plot a graph of frequency against kinetic energy on the graph paper provided. (4) 12.1.5 From the graph, determine the threshold frequency of the metal. (2) 12.2 White light is shone through cold hydrogen gas. A spectrum is produced when the emerging light is dispersed by a triangular prism and cast on a screen. 12.2.1 Name the type of spectrum produced. (1) 12.2.2 Describe the pattern observed on the screen. (2) 12.2.3 Explain the pattern observed. (3) [15] [125] Copyright reserved Please turn over 7