2024 NYJC H2 PHY 9749 P3

NYJC 2024 9749/03/J2Prelim/24 [Turn over NANYANG JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME CLASS TUTOR’S NAME CENTRE NUMBER S INDEX NUMBER PHYSICS 9749/03 Paper 3 Longer Structured Questions 13 September 2024 2 hours Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your name, class, Centre number 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 a 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 Examiner’s Use Section A 1 / 9 2 / 8 3 / 12 4 / 9 5 / 12 6 / 10 Section B 7 / 20 8 / 20 Total / 80 This document consists of 23 printed pages. H

2 NYJC 2024 9749/03/J2Prelim/24 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 Formulae uniformly accelerated motion s = 21 2ut at+ v2 = u2 + 2as work done on / by gas W = pV hydrostatic pressure p = gh gravitational potential  = Gm r− temperature T / K = T/°C + 273.15 pressure of an ideal gas p = 21 3 Nm cV  mean translational kinetic energy of an ideal gas molecule E = 3 2 kT displacement of particle in s.h.m. x = 0 sinxt  velocity of particle in s.h.m. v = 0 cosvt  = 22 0xx− electric current I = Anvq resistors in series R = R1 + R2 + … resistors in parallel 1/R = 1/R1 + 1/R2 + … electric potential V = 04 Q r alternating current/voltage x = 0 sinxt  magnetic flux density due to a long straight wire B = 0 2 d   I magnetic flux density due to a flat circular coil B = 0 2r  NI magnetic flux density due to a long solenoid B = 0 nI radioactive decay x = 0 exp( )−xt decay constant  = 1 2 ln2 t

3 NYJC 2024 9749/03/J2Prelim/24 [Turn over Section A Answer all the questions in the spaces provided. 1 (a) (i) Define impulse. [1] (ii) State the principle of conservation of linear momentum. [2] (b) Two isolated objects, X and Y travel along the same straight line with speeds 3.5 m s−1 and 2.0 m s −1 respectively as shown in Fig. 1.1 . The objects collide elastically and continue to travel along the same straight line after the collision. Object X has a mass of 0.5 kg and object Y has a mass of 0.25 kg. The variation with time of the force exerted by object X on object Y during the collision is shown in Fig. 1.2. force Fig. 1.2 0 0 time X Y 3.5 m s−1 2.0 m s−1 Fig. 1.1

4 NYJC 2024 9749/03/J2Prelim/24 (i) Sketch on Fig. 1.2 the variation with time of the force exerted by object Y on object X during the collision. Label this line F. [1] (ii) State and ex plain whether, during the collision it is possible for both objects to be at rest simultaneously. [2] (iii) The area under the graph given in Fig. 1. 2 is 0.50 N s. Use the information in (b) to calculate the velocity of object Y after the collision. velocity of object Y = m s−1 [3] [Total: 9]

5 NYJC 2024 9749/03/J2Prelim/24 [Turn over 2 (a) A student performs an experiment to determine the specific latent heat of fusion of ice. The student has two sets of apparatus next to each other on the laboratory bench, as shown in Fig. 2.1 and Fig. 2.2. Both funnels are identical and have the same mass of crushed ice at 0 C. The current in the heater is 5.0 A and the potential difference across it is 12 V. Fig. 2.3 shows the variation of mass of water m collected in each beaker with time t. Fig. 2.3 (i) Explain why the gradients of the two graphs are different. [1] 0 1.0 2.0 3.0 4.0 beaker in Fig. 2.1 0 20 40 60 m / 10–3 kg t / minutes beaker in Fig. 2.2 to power supply clamp clamp crushed ice heater funnel bench water beaker beaker funnel water crushed ice Fig. 2.1 Fig. 2.2

6 NYJC 2024 9749/03/J2Prelim/24 pressure volume A D C B 0 0 (ii) Use Fig. 2.3 to show that the specific latent heat of fusion of ice is about 3  105 J kg−1. specific latent heat of fusion = J kg−1 [2] (b) A heat engine, such as a car engine, is a device that converts thermal energy into mechanical work. When the heat engine operates, a fixed amount of gas expands and contracts repeatedly in a cylinder with a piston. The cycle of expansion and contraction for a fixed quantity of an ideal gas is illustrated graphically in Fig. 2.4. Fig. 2.4 There are four stages in the cycle. Stage Description A to B a slow compression of the gas at constant temperature B to C a sudden compression of the gas causing an increase in temperature C to D a slow expansion of the gas at constant temperature D to A a sudden expansion back to its original pressure, volume, and temperature

7 NYJC 2024 9749/03/J2Prelim/24 [Turn over (i) Explain each of the following facts about the cycle: 1 During stage B to C, the piston causes a sudden compression of the gas, causing an increase in temperature, with reference to the kinetic theory of gases. [1] 2 At the end of all four stages, the change in internal energy of the gas is zero. [1] (ii) Complete the table in Fig. 2.5 for the cycle. stage thermal energy supplied to gas / J work done on gas / J increase in internal energy of gas / J A to B –702 702 0 B to C 0 844 844 C to D 936 –936 0 D to A 0 Fig. 2.5 [1] (iii) Determine the efficiency of the heat engine. Show your working clearly. efficiency = % [2] [Total: 8]

8 NYJC 2024 9749/03/J2Prelim/24 3 Fig 3.1 shows a displacement -distance graph for two sound waves, A and B, of the same frequency and amplitude at a particular instant. Wave A is travelling to the right and wave B is travelling to the left. (a) (i) Using Fig. 3.1, determine the wavelength of the two waves. wavelength = m [2] (ii) The frequency of the sound is determined to be 469 Hz. Calculate the speed of sound to 4 significant figures. speed = m s−1 [1] (iii) The frequency and the wavelength of the sound were determined to a precision of  5% and  8% respectively. Write