ACJC 2023 J2 H2 Physics Prelim P3

This paper consists of 26 printed pages Anglo-Chinese Junior College Physics Preliminary Examination Higher 2 CANDIDATE NAME CLASS CENTRE NUMBER S 3 0 0 4 INDEX NUMBER PHYSICS Paper 3 Longer Structured Questions Candidates answer on the Question Paper. No Additional Materials are required. 9749/03 30 August 2023 2 hours READ THESE INSTRUCTIONS FIRST Write your name, class and index number in the spaces at the top of this page. Write in dark blue or black pen on both sides of the paper. You may use an HB pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, glue or correction fluid. The use of an approved scientific calculator is expected, where appropriate. Section A Answer all questions. Section B Answer one question only. You are advised to spend one and a half hours on Section A and half an hour on Section B. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiners’ use only Section A 1 / 12 2 / 11 3 / 11 4 / 12 5 / 14 Total / 60 Section B 6 / 20 7 / 20 Grand Total / 80

2 Anglo-Chinese Junior College 2023 J2 H2 9749 Paper 3 Preliminary Examination DATA AND FORMULAE Data speed of light in free space, c = 3.00  108 m s−1 permeability of free space, o = 4  10−7 H m−1 permittivity of free space, o = 8.85  10−12 F m–1 (1/(36))  10–9 F m–1 elementary charge, e = 1.60  10−19 C the Planck constant, h = 6.63  10−34 J s unified atomic mass constant, u = 1.66  10−27 kg rest mass of electron, me = 9.11  10−31 kg rest mass of proton, mp = 1.67  10−27 kg molar gas constant, R = 8.31 J K−1 mol−1 the Avogadro constant, NA = 6.02  1023 mol−1 the Boltzmann constant, k = 1.38  10−23 J K−1 gravitational constant, G = 6.67  10−11 N m2 kg−2 acceleration of free fall, g = 9.81 m s−2

3 [Turn over Anglo-Chinese Junior College 2023 J2 H2 9749 Paper 3 Preliminary Examination Formulae uniformly accelerated motion, s = ut + 2 1 at 2 v 2 = u 2 + 2as work done on/by a gas, W = p V hydrostatic pressure, p =  g h gravitational potential,  = − Gm r temperature T/K = T/oC + 273.15 pressure of an ideal gas p = 21 3 Nm c V  mean translational kinetic energy of an ideal gas molecule, E = 3 2 kT displacement of particle in s.h.m., x = xo sin t velocity of particle in s.h.m., v = vo cos t =   22 oxx − electric current I = Anvq resistors in series, R = R1 + R2 +  resistors in parallel, 1/R = 1/R1 + 1/R2 +  electric potential, V = 4 o Q r alternating current/voltage, x = xo sin t magnetic flux density due to a long straight wire B = 2 o d   magnetic flux density due to a flat circular coil B = 2 oN r  magnetic flux density due to a long solenoid B = on radioactive decay, x = xo exp(−t) decay constant,  = 12 ln2 t

4 Anglo-Chinese Junior College 2023 J2 H2 9749 Paper 3 Preliminary Examination For Examiner’s Use Section A Answer all the questions in this Section in the spaces provided. 1 (a) Fig. 1.1 shows two identical balls on a smooth surface. Ball A moves with a speed of v m s–1 towards a stationary ball B. Fig. 1.1 Explain why it is not possible for ball A to move in the opposite direction after colliding with ball B. …………………………………………………………………………………………….. …………………………………………………………………………………………….. …………………………………………………………………………………………….. …………………………………………………………………………………………….. ……………………………………………………………………………………….... [2] (b) Fig. 1.2 shows a 2.5 kg crate moving towards a stationary 2.0 kg crate on a smooth surface. Fig. 1.2 The two crates collide elastically. (i) Determine the speed of the 2.5 kg crate after collision. speed = ……………………… m s–1 [3]

5 [Turn over Anglo-Chinese Junior College 2023 J2 H2 9749 Paper 3 Preliminary Examination For Examiner’s Use (ii) The collision takes place over a period of 0.50 s. Determine the average force that the 2.5 kg crate exerts on the 2.0 kg crate. average force = ……………………… N [2] (c) The crates are carrying tomatoes . A particular 3.0 kg crate has a speed of 1.5 m s–1 just before it slides down a 2.0 m high rough slope inclined an at an angle of 30° to the horizontal as shown in Fig. 1.3. Fig. 1.3 An average frictional force of 15 N is exerted on the crate as it slides down the slope. (i) Determine the speed of the crate when it reaches the bottom of the slope. speed = ……………………… m s–1 [3]

6 Anglo-Chinese Junior College 2023 J2 H2 9749 Paper 3 Preliminary Examination For Examiner’s Use (ii) A co-worker suggested to replace the rough slope with a smooth one so that the crate can reach the bottom of the slope in a shorter time. Suggest and explain a possible reason why this suggestion should not be implemented. ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… …………………………………………………………………………………..… [2] [Total: 12]

7 [Turn over Anglo-Chinese Junior College 2023 J2 H2 9749 Paper 3 Preliminary Examination For Examiner’s Use 2 (a) Define electric field strength at a point. …………………………………………………………………………………………….. …………………………………………………………………………………………….. …………………………………………………………………………………………….. ……………………………………………………………………………………….... [2] (b) A positively charged conducting sphere P, isolated in space, has a radius R. The electric field strength at the surface of the sphere is E. (i) P has a charge of 2.2  10–9 C and a diameter of 4.0 cm. Determine the electric field strength at the surface of the sphere. electric field strength = ……………………… N C–1 [2]

8 Anglo-Chinese Junior College 2023 J2 H2 9749 Paper 3 Preliminary Examination For Examiner’s Use (ii) On Fig. 2.1, sketch a graph to show the variation of the electric field strength of the sphere with distance from its centre until 8.0 cm. Fig. 2.1 [3]

9 [Turn over Anglo-Chinese Junior College 2023 J2 H2 9749 Paper 3 Preliminary Examination For Examiner’s Use (c) Fig. 2.2 shows another positively conducting charged sphere Q, of the same magnitude of charge, placed at a close distance from P. Fig. 2.2 (i) On Fig. 2.2, draw electric field lines to represent the electric field around the two spheres. [2] (ii) Explain why the equipotential lines are always perpendicular to the electric field lines. ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… …………………………………………………………………………………..… [2] [Total: 11]

10 Anglo-Chinese Junior College 2023 J2 H2 9749 Paper 3 Preliminary Examination For Examiner’s Use 3 (a) Explain what is meant by magnetic flux linkage. …………………………………………………………………………………………….. ……………………………………………………………………………………….... [1]