ASRJC 2024 JC2 H2 Physics Prelim P2

1 9749/02/ASRJC/2024PRELIM [Turn over Name: _____________________________ ( ) Class: 24 / ______ 2024 JC2 Preliminary Examination PHYSICS Higher 2 9749/02 Paper 2 Structured Questions Tuesday 10 September 2024 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. Do not use staples, paper clips, glue or correction fluid. The use of an approved scientific calculator is expected, where appropriate. Answer all questions. The number of marks is given in brackets [ ] at the end of each question or part question. This document consists of 23 printed pages and 1 blank page. For Examiner’s Use Paper 2 (80 marks) 1 2 3 4 5 6 7 8 Deductions Total ANDERSON SERANGOON JUNIOR COLLEGE

2 9749/02/ASRJC/2024PRELIM Data speed of light in free space c = 3.00  108 m s−1 permeability of free space 0 = 4  10−7 H m−1 permittivity of free space 0 = 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 9749/02/ASRJC/2024PRELIM [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/2024PRELIM Answer all the questions in the spaces provided. 1 (a) State the principle of conservation of linear momentum. …………………………………………………………………………………………….……….. ………………………………………………………………………………………….………….. …………………………………………………………………………………………….......... [2] (b) Along a horizontal frictionless surface, ball A moves with speed v towards a stationary ball B as shown in Fig. 1.1. Ball A has mass 4.0 kg and ball B has mass 12 kg. The balls collide and then move apart as shown in Fig. 1.2. Ball A has velocity 6.0 m s−1 at an angle of  to the direction of its initial path. Ball B has velocity 3.5 m s−1 at an angle of 30° to the direction of the initial path of ball A. (i) By considering the components of momentum at right−angles to the direction of the initial path of ball A, determine  .  = ° [2] (ii) Hence, determine the initial speed v of ball A. v = ……………………………. m s−1 [2] Fig. 1.1 Fig. 1.2

5 9749/02/ASRJC/2024PRELIM [Turn Over (iii) State and explain whether the collision is elastic or inelastic. ……………………………………………………………………………………………….. ……………………………………………………………………………….………….... [2] [Total: 8]

6 9749/02/ASRJC/2024PRELIM 2 A spring is kept horizontal by attaching it to points A and B, as shown in Fig. 2.1 Point A is on a movable slider and point B is on a fi xed support. A cart of mass 1.7 kg has horizontal velocity v towards the slider. The cart collides with the slider. The spring compressed as the cart comes to rest. The variation of compression x of the spring with force F exerted on the spring is shown in Fig. 2.2. Fig. 2.2 shows the compression of the spring for F = 1.5 N to F = 4.5 N. The cart comes to rest when F is 4.5 N. (a) Use Fig. 2.2 to (i) show that the compression of the spring obeys Hooke’s law, [2] Fig. 2.1 Fig. 2.2

7 9749/02/ASRJC/2024PRELIM [Turn Over (ii) determine the elastic potential energy EP stored in the spring when the cart is brought to rest. EP = …………………………….J [2] (b) Calculate the speed v of the cart as it makes contact with the slider. Assume that all the kinetic energy of the cart is converted to the elastic potential energy of the spring. speed = …………………. m s−1 [2] [Total: 6]

8 9749/02/ASRJC/2024PRELIM 3 A beam of unpolarised light is incident normally on a polaroid P as shown in Fig. 3.1. The polarised light after passing through polaroid P has amplitude A and intensity Io. Fig. 3.1 The polarised light from polaroid P then passes through polaroid Q whose polarisation axis is inclined at an angle θ to the polarisation axis of polaroid P. This polarised light from Q has amplitude A cos θ. (a) In Fig. 3.2 , sketch a graph showing the variation of intensity of the polarised light from polaroid Q when it is rotated through  = 0° to  = 360°. Label all values on the axes. Fig. 3.2 [2] unpolarised light polarisation axis polarisation axis polaroid P polaroid Q eye intensity θ /° 0 polarised light amplitude A intensity Io A cos θ amplitude

9 9749/02/ASRJC/2024PRELIM [Turn Over (b) Polaroid Q is now fixed with its polarisation axis kept at 90° to that of polaroid P. A third polaroid R is then inserted between polaroids P and Q, with its polarisation axis inclined at an angle ϕ to the polarisation axis of polaroid P, as shown in Fig. 3.3. Fig. 3.3 (i) Calculate the intensity of the polarised light from polaroid Q in terms of Io when ϕ is 30°. intensity = ……………………………. [2] (ii) In Fig. 3.4 , sketch a graph showing the variation of intensity of the polarised light from polaroid Q when polaroid R is rotated through ϕ = 0° to ϕ = 360°. Label all values on the axes. Fig. 3.4 [3] (c) Explain why longitudinal waves cannot be polarised. …………………………………………………………………………………………….............. . …………………………………………………………………………………………….......... [1] polarization axis polarization axis polarization axis θ = 900 Polaroid P Polaroid R Polaroid Q unpolarised light polarisation axis polaroid P polarisation axis polarisation axis kept at 90° polaroid R polaroid Q eye intensity ϕ /° 0