TEACHER S CLUB EXAMS GRADE 11. PHYSICAL SCIENCES: PHYSICS Paper 1

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1 TEACHER S CLUB EXAMS GRADE 11 PHYSICAL SCIENCES: PHYSICS Paper 1 MARKS: 150 TIME: 3 hours INSTRUCTIONS AND INFORMATION 1. This question paper consists of 12 pages, two data sheets and a sheet of graph paper. 2. Answer ALL the questions. 3. Answer Question 7.2 on the graph paper. 4. You may use non-programmable calculators. 5. You may use appropriate mathematical instruments. 6. Number the answers correctly according to the numbering system used in this question paper. 7. Data sheets are attached for your use. 8. Wherever motivation, discussion, et cetera is required, write brief answers.

2 Section A Question 1: One-word items Give ONE word/term for each of the following descriptions. Write only the word/ term next to the question number ( ) on the attached ANSWER SHEET. 1.1 Change in momentum (1) 1.2 The unit of measure of sound intensity (1) 1.3 Region of space in which an electric charge experiences a force (1) 1.4 The work done in moving a charge between two points in a circuit (1) 1.5 Rate of change of magnetic flux (1) [5] Question 2: False items Each statement below is FALSE. Write down the correct statement next to the question number ( ). Do not correct the statements with a negative statement, i.e. IS NOT, will not be accepted as the correct answer. 2.1 A stationary object has no forces acting on it. (2) 2.2 In an inelastic collision, only kinetic energy is conserved. (2) 2.3 Whole number multiples of the fundamental frequency are called octaves. (2) 2.4 A converging lens only forms real images. (2) 2.5 When resistors are connected in parallel, they are referred to as potential dividers. (2) [10] Maskew Miller Longman, Focus on Physical Sciences Grade 11 Physics: Paper 1 Page 2 of 15

3 Question 3: Multiple choice Four options are given as possible answers to the following questions. Each question has ONE correct answer. Choose the correct answer and next to the question number ( ) write down the letter of the correct answer. 3.1 A 5 kg box is at rest on the floor. The surface area of the box in contact with the floor is 0,5 m 2. When a force F is applied to the box, it moves with a velocity v. The same box is turned on its end so that the surface area in contact with the floor is 0,25 m 2. For the box to move with the same velocity v, the force that must be applied is: A 2F B ½ F C 4F D F (2) 3.2 A learner decides to increase the volume on her radio. Which one of the following characteristics of sound will increase if the volume increases? A wavelength B amplitude C frequency D velocity (2) 3.3 The acceleration due to the gravity of a planet is A directly proportional to the square of the radius of the planet. B directly proportional to the mass of the planet. C inversely proportional to the radius of the planet. D inversely proportional to the mass of the planet. (2) Maskew Miller Longman, Focus on Physical Sciences Grade 11 Physics: Paper 1 Page 3 of 15

4 3.4 A capacitor is connected to a battery as shown below. Which one of the following graphs best explains the change in ammeter reading with time from the instant the uncharged capacitor is connected to the time when it is fully charged? A B I (A) I (A) t (s) t (s) C D I (A) I (A) t (s) t (s) (2) Maskew Miller Longman, Focus on Physical Sciences Grade 11 Physics: Paper 1 Page 4 of 15

5 3.5 Consider the electrical circuit below. If bulb Y burns out, how will the ammeter and voltmeter readings change? Ammeter reading Voltmeter reading A becomes zero becomes zero B increases increases C decreases decreases D becomes zero increases (2) [10] Total Section A: 25 Maskew Miller Longman, Focus on Physical Sciences Grade 11 Physics: Paper 1 Page 5 of 15

6 Section B Instructions and information 1. Answer Question 8.3 on the graph paper. 2. Show formulae and substitutions in ALL your calculations. 3. Round off your answers to TWO decimal places. Question State the principle of conservation of momentum. (2) 4.2 A bullet, mass 20 g, takes s to emerge from the barrel of a rifle when it is fired. The mass of the rifle is 7 kg. If the force acting on the bullet is N, calculate: the velocity of the bullet the moment it emerges from the barrel. (5) the recoil velocity of the rifle. (4) [11] Question The effects of frictional forces can often be undesirable, yet friction is desirable in many cases. Why are the effects of friction undesirable (2) desirable? (2) 5.2 A 50 kg box is placed on an inclined plane making an angle of 30 with the horizontal. The coefficient of sliding friction is 0, Draw a free-body diagram of all forces acting on the box. Label the forces. (5) Calculate the resultant force acting on the box. (10) [19] Maskew Miller Longman, Focus on Physical Sciences Grade 11 Physics: Paper 1 Page 6 of 15

7 Question 6 A painter stands on a horizontal, uniform scaffolding that is hung by its ends from two vertical ropes A and B, which are 5 m apart. The scaffold weighs 20 kg. The tension in rope A is 600 N and that in rope B is 200 N. 6.1 Calculate the weight of the painter. (5) 6.2 How far from rope A is the painter standing? (6) [11] Question 7 An object that is 3 mm tall is viewed through a simple reading glass of focal length 20 mm. The object is 10 mm from the lens. 7.1 Define the concept focal length of a convex lens. (1) 7.2 Draw an accurate ray diagram to determine the position of the image formed by the reading glass. (6) 7.3 Write down three properties of this image. (3) 7.4 Calculate the magnification. (3) [13] Maskew Miller Longman, Focus on Physical Sciences Grade 11 Physics: Paper 1 Page 7 of 15

8 Question Study the position time graphs (A, B, C, D) representing different sound waves What type of wave is a sound wave? (1) Which sound wave has the highest frequency? What is the frequency of this sound wave? (3) Which graph represents the loudest sound with the lowest pitch? (1) Calculate the speed of the sound in graph A. (4) 8.2 A toy siren makes vibrations of constant frequency. The siren sends out waves 10 cm long through medium A and 15 cm long through medium B. The velocity of the wave in A is 90 cm s 1. Calculate the velocity of the wave in B. (5) [14] Maskew Miller Longman, Focus on Physical Sciences Grade 11 Physics: Paper 1 Page 8 of 15

9 Question 9 A guitar string vibrates with the standing wave shown below. 9.1 Define the concept fundamental frequency of the string. (1) 9.2 What is the wavelength of this standing wave? (2) 9.3 Write an expression for the frequency of this harmonic in terms of the length L and velocity. (3) [6] Question 10 Two charged pith balls, A and B, are enclosed in a vacuum as shown below. Pith ball A is suspended above pith ball B. The mass of each pith ball is 2 g. Pith ball B has a charge of 6 µc What is the charge on pith ball A? Give a reason for your answer. (2) 10.2 If pith ball A is 5 cm above the centre of sphere B, what is the charge on A? (6) [8] Maskew Miller Longman, Focus on Physical Sciences Grade 11 Physics: Paper 1 Page 9 of 15

10 Question 11 The diagram below shows a circuit with a 2,5 µf capacitor connected to a 12 V battery in series with a 280 Ω resistor. After a specific time, t, the potential difference across the capacitor has increased to 2 V. You can ignore the internal resistance of the battery. Switch S is now closed Calculate the initial charging current. (3) 11.2 What is the potential difference across the resistor after time t? (2) 11.3 Calculate the current when the potential difference across the capacitor is 2 V. (2) 11.4 At what rate is the potential difference across the capacitor increasing? (4) [11] Question 12 A circular coil of wire of radius 2 cm has 50 turns. A magnet creating a magnetic field of 0,05 T is pulled quickly from inside the coil until it is far enough away for the field to become zero in 0,2 s State Faraday s Law of electromagnetic induction. (1) 12.2 Calculate the emf induced in the coil during t = 0 s to t = 0,2 s. (6) [7] Maskew Miller Longman, Focus on Physical Sciences Grade 11 Physics: Paper 1 Page 10 of 15

11 Question 13 In the circuit below, a 12 V battery of negligible internal resistance is connected to an arrangement of resistors. R x Calculate the value of R x if the total resistance of the circuit is equal to R x. (5) Calculate the current flowing through the 20 Ω resistor. (5) 13.2 A transformer with negligible power loss is connected to a 120 V input and the secondary feeds into a load of 2, Ω. The windings have 600 turns in the primary and turns in the secondary Calculate the output potential difference. (3) Calculate the power delivered to the load. (3) 13.3 What type of pollution could exist near a nuclear power station such as Koeberg? What effect would this have on the environment? (2) [18] Maskew Miller Longman, Focus on Physical Sciences Grade 11 Physics: Paper 1 Page 11 of 15

12 Question 14 The development of computers is a result of the properties of semiconductors such as silicon What are semiconductors? (1) 14.2 The diagram below shows a diode Identify the type of diode illustrated above. (1) What is the function of the diode? (2) A learner states that the above diode is reverse-biased. Do you agree? Give a reason for your answer. (3) [7] Total Section B: 125 Grand total: 150 Maskew Miller Longman, Focus on Physical Sciences Grade 11 Physics: Paper 1 Page 12 of 15

13 DATA FOR PHYSICAL SCIENCES GRADE 11 PHYSICS: Paper 1 TABLE 1: PHYSICAL CONSTANTS NAME SYMBOL VALUE Acceleration due to gravity g 9,8 m s 2 Speed of light in a vacuum c 3, m s 1 Gravitational constant G 6, N m 2 kg 2 Coulomb s constant k 9, N m 2 C 2 Charge on electron e 1, C Electron mass m e 9, kg Permittivity of free space ε 0 8, F m 1 TABLE 2: FORMULAE MOTION v f = v i + aδt v f 2 = v i 2 + 2aΔx Δx = v i Δt = 1 2 aδt2 Δx = ( v + v f i 2 ) Δt FORCE F net = ma p = mv F = Gm m 1 2 FΔt = Δp = mv mu r 2 μ s = f s(max) N μ = f k k N WEIGHT AND MECHANICAL ENERGY F g = mg U = E p = mgh K = E k = 1 2 mv2 Maskew Miller Longman, Focus on Physical Sciences Grade 11 Physics: Paper 1 Page 13 of 15

14 WAVES, LIGHT AND SOUND v = f λ or v = v λ T = 1 f or T = 1 v ELECTROSTATICS F = kq Q 1 2 ( k = 9,0 10 r 2 9 N m 2 C-2 ) E = F q E = kq r 2 ( k = 9, N m 2 C -2 ) E = V d V = W Q W = QEs U = kq Q 1 2 r (k = 9,0 109 N m 2 C -2 ) C = Q V C = e 0 A d ELECTROMAGNETISM e = N ΔΦ Δt V s V = N s p N p Φ = BA F = qvb CURRENT ELECTRICITY I = Q Δt emf = I(R + r) R = V I R = r 1 + r 2 + r R = 1 r r r 3 + Maskew Miller Longman, Focus on Physical Sciences Grade 11 Physics: Paper 1 Page 14 of 15

15 GRAPH PAPER QUESTION mm L Maskew Miller Longman, Focus on Physical Sciences Grade 11 Physics: Paper 1 Page 15 of 15