ASRJC 2022 Prelim P2

1 9749/02/ASRJC/2022PRELIM [Turn Over Name: _____________________________ ( ) Class: 22 / ______ 2022 JC2 Preliminary Examination PHYSICS Higher 2 9749/02 Paper 2 Structured Questions Tuesday 13 September 2022 2 hours Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your name, class index number and class 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 or graphs. The use of an approved scientific calculator is expected, where appropriate. Answer all questions. 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. This document consists of 21 printed pages and 3 blank pages. For Examiner’s Use Paper 2 (80 marks) 1 / 12 2 / 8 3 / 15 4 / 10 5 / 5 6 / 10 7 / 20 Deduct Total ANDERSON SERANGOON JUNIOR COLLEGE

2 9749/02/ASRJC/2022PRELIM Data speed of light in free space c = 3.00 x 108 m s-1 permeability of free space 0 = 4 x 10-7 H m-1 permittivity of free space 0 = 8.85 x 10-12 F m-1 (1/(36)) x 10-9 F m-1 elementary charge e = 1.60 x 10-19 C the Planck constant h = 6.63 x 10-34 J s unified atomic mass constant u = 1.66 x 10-27 kg rest mass of electron me = 9.11 x 10-31 kg rest mass of proton mp = 1.67 x 10-27 kg molar gas constant R = 8.31 J K-1 mol-1 the Avogadro constant NA = 6.02 x 1023 mol-1 the Boltzmann constant k = 1.38 x 10-23 J K-1 gravitational constant G = 6.67 x 10-11 N m2 kg-2 acceleration of free fall g = 9.81 m s-2

3 9749/02/ASRJC/2022PRELIM [Turn Over Formulae uniformly accelerated motion =s 2 2 1 atut + =2v asu 22 + work done on/by a gas =W Vp hydrostatic pressure =p gh gravitational potential = r Gm− temperature T/K = T/C + 273.15 pressure of an ideal gas p =  2 3 1 cV Nm mean translational kinetic energy of an ideal gas molecule =E kT2 3 displacement of particle in s.h.m. x = x0 sin  t velocity of particle in s.h.m. v = v0 cos  t = 22 xxo − electric current I = Anvq resistors in series R = R1 + R2 + … resistors in parallel 1/R = 1/R1 + 1/R2 + … electric potential V = r Q o4 alternating current/voltage x = x0 sin  t magnetic flux density due to a long straight wire B = d o   2 I magnetic flux density due to a flat circular coil B = r No 2 I magnetic flux density due to a long solenoid B = Ino radioactive decay x = x0 exp(–t) decay constant  = 2 1 2ln t

4 9749/02/ASRJC/2022PRELIM Answer all the questions in the spaces provided. 1 (a) Use Newton’s Laws to deduce the principle of conservation of momentum. [3] (b) Fig. 1.1 shows the variation with time of momentum for two colliding bodies P and Q. Fig. 1.1 The mass of bodies P and Q are 2.0 kg and 4.0 kg respectively. (i) Explain why the gradients of the graphs during collision have opposite sign. ………………………………………………………………………………….................... ………………………………………………………………………………….................... ……………………………………………………………………………….………….... [1] time / ms 0 100 200 300 400 500 0 momentum / kg m s−1 10 20 30 P Q

5 9749/02/ASRJC/2022PRELIM [Turn Over (ii) State the condition under which the momentum is conserved. ………………………………………………………………………………….................... ……………………………………………………………………………….………….... [1] (iii) Show that the momentum is conserved when the two bodies collide. [1] (iv) Calculate the magnitude of the force acting on body P during the collision. force = …………………………….N [2] (v) Calculate the magnitude of the impulse on body Q during the collision. impulse = …………………………….N s [1] (vi) By considering quantitively the relative speeds of approach and of separation of the two bodies, deduce whether the collision is elastic, inelastic or perfectly inelastic. type of collision: ……………………………………[3] [Total: 12]

6 9749/02/ASRJC/2022PRELIM 2 A student sets out to investigate the oscillation of a mass suspended from the free end of a spring, as illustrated in Fig. 2.1. Fig. 2.1 The mass is pulled downwards and then released. The variation with time t of the displacement y of the mass is shown in Fig. 2.2. Fig. 2.2 (a) Use information from Fig. 2.2 (i) to explain why the graph suggests that the oscillations are undamped, ……………………………………………………………………………………………. [1]

7 9749/02/ASRJC/2022PRELIM [Turn Over (ii) to calculate the angular frequency of the oscillations, angular frequency = ……………………………….. rad s−1 [2] (iii) to determine the maximum speed of the oscillating mass. speed = ……………………………………….. m s–1 [2] (b) (i) Determine the resonant frequency f0 of the mass-spring system. f0 = …………………………… Hz [1] (ii) The student finds that if short impulsive forces of frequency ½ f0 are impressed on the mass-spring system, a large amplitude of oscillation is obtained. Explain this observation. …………………………………………………………………………………………..…… …………………………………………………………………………………………..…… ………………………………………………………………………………………….… [2] [Total: 8]

8 9749/02/ASRJC/2022PRELIM 3 (a) A satellite passing the planet Neptune communicates with its controller on the Earth using a microwave transmitter with output power 25 W and wavelength 80 mm. Neptune is 4.4  1012 m from the Earth at the time when the communication takes place. (i) State whether the microwaves are longitudinal or transverse. …………………………………………………………………………………………...… [1] (ii) Calculate the time taken for a signal to travel from the satellite to the Earth. time taken = ……………………………. s [1] (iii) Assuming the power transmitted by the satellite is radiated uniformly in all directions, calculate the power received on Earth by a dish aerial of effective area 280 m2. power = ……………………………. W [3] (iv) The actual power received at the dish aerial is 1.2  10–15 W. Suggest why the actual power received is greater than that calculated in (a)(iii). ……………………………………………………………………………………………….. ……………………………………………………………………………….………….... [1]

9 9749/02/ASRJC/2022PRELIM [Turn Over (b) Circular water waves are produced by vibrating dippers at points P and Q, as shown in Fig. 3.1. Fig. 3.1 The waves from P alone have the same amplitude at point R as the waves from Q alone. Distance PR is 44 cm and distance QR is 29 cm. The dippers vibrate in phase with a period of 1.5 s to produce waves of speed 4.0 cm s−1. (i) Determine the wavelength of the waves. wavelength = ……………………………. m [2] (ii) By reference to the distances PR and QR, explain why the water particles are at rest at point R. ………………………………………………………………………………….................... ……………………………………………………………………………………………….. ……………………………………………………………………………………………….. ………………………………………………………………………………….................... ……………………………………………………………………………….………….... [3]

10 9749/02/ASRJC/2022PRELIM (c) A loudspeaker is held above a vertical tube of liq