(DHS) 2024 Prelim Phy P3 final

© DHS 2024 9749/03 [Turn over Name: Centre/Index Number: Class: DUNMAN HIGH SCHOOL Preliminary Examination Year 6 H2 PHYSICS Paper 3 Longer Structured Questions Candidates answer on the Question Paper 9749/03 18 September 2024 2 hours READ THESE INSTRUCTIONS FIRST Write your centre number, index number, name and class at the top of this page. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Section A Answer all questions. Section B Answer any one question. The use of an approved scientific calculator is expected, where appropriate. You may lose marks if you do not show your working or if you do not use appropriate units. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use Section A 1 10 2 7 3 11 4 11 5 11 6 10 Section B 7 / 8 20 Total 80 This document consists of 25 printed pages and 3 blank pages.

2 © DHS 2024 9749/03 [Turn over 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 © DHS 2024 9749/03 [Turn over Formulae uniformly accelerated motion, s = ut + at2 v2 = u2 + 2as work done on/by a gas, W = pV hydrostatic pressure, p = gh gravitational potential,  = −Gm/r temperature, T/K = T/oC + 273.15 pressure of an ideal gas, p = mean translational kinetic energy of an ideal gas molecule, E = displacement of particle in s.h.m., x = x0 sin t velocity of particle in s.h.m., v = v0 cos t =  electric current, I = Anvq resistors in series, R = R1 + R2 + . . . resistors in parallel, 1/R = 1/R1 + 1/R2 + . . . electric potential, V = alternating current / voltage, x = x0 sin t magnetic flux density due to a long straight wire, B = magnetic flux density due to a flat circular coil, B = magnetic flux density due to a long solenoid, B = radioactive decay, x = x0 exp(−t) decay constant,  = 1 2 21 3 Nm cV  kT2 3 22 xxo − r Q o4 0 2 d I  0 2 N r I 0nI 1 2 ln2 t

4 © DHS 2024 9749/03 Section A Answer all the questions in this section in the spaces provided. 1 (a) State the two conditions necessary for the equilibrium of a body acted upon by a number of forces. 1. ………...………………………………………………………………………………….... …...…………………………………………………………………………………………….…. 2. …...…………………………………………………………………………………........... ……………………………………………………………………………………………….…. [2] (b) A non-uniform beam of mass 20 kg and length 5.0 m is supported by a cable and hinged to the wall as shown in Fig. 1.1. The beam supports a mass of 5.0 kg at one end and is in equilibrium. Fig. 1.1 (i) On Fig. 1.1, draw a free body diagram of the forces acting on the beam. [2] 50º 70º 5.0 kg hinge beam cable

5 © DHS 2024 9749/03 [Turn over (ii) If the tension in the cable is 120 N, calculate the position of the centre of gravity of the beam from the hinge. centre of gravity = ………….….………… m [2] (iii) Calculate the magnitude and direction of the force acting by the wall on the beam. force = ……………….………….. N direction = ………………….….……………with the beam [4] [Total: 10]

6 © DHS 2024 9749/03 2 A metal ball of mass 50 g travels in a horizontal circle of radius 10 cm around a smooth cone as shown by Fig 2.1. The metal ball makes 3.0 revolutions every second. (a) Explain why the metal ball in uniform circular motion is said to experience an acceleration. ………….…...………………………………………………………………………………….... …...…………………………………………………………………………………………….…. ………….…...………………………………………………………………………………….... ……………………………………………………………………………………………….…. [2] (b) (i) Show that tan  = g r 2 where 𝜃 is shown in Fig. 2.1, r is the radius of the horizontal circle and  is the angular velocity of the metal ball. [2] Fig. 2.1

7 © DHS 2024 9749/03 [Turn over (ii) Hence determine .  = ………….……………… o [2] (c) The angular velocity  of the metal ball is now increased. Sketch, on Fig. 2.2, a graph to show the variation with angular velocity , of the radius r of the horizontal circle of the metal ball around the cone. [1] [Total: 7] 3 A scuba diver releases an air bubble, of diameter 3.0 cm from a depth of 14 m below the sea level. The air is assumed to behave like an ideal gas and the temperature of the water is constant at 25°C. (a) (i) Explain how molecular movement of the gas molecules inside the air bubble causes pressure exerted by the gas. .……………………………………………………………………………….……………. .……………………………………………………………………………….……………. .……………………………………………………………………………….……………. .……………………………………………………………………………….……………. ..………………………………………………………………………………………… [3] r  Fig. 2.2

8 © DHS 2024 9749/03 (ii) Given that the pressure at a depth of 14 m below the surface is 2.4 × 105 Pa, and the density of water is 1000 kg m-3. Calculate the volume of the air bubble when it reaches the surface of the water. volume of air bubble = ………….……………… m3 [2] (b) (i) State the First Law of Thermodynamics. .……………………………………………………………………………….……………. .……………………………………………………………………………….……………. .……………………………………………………………………………….………… [2] (ii) State and explain whether heat is added or removed from the air bubble as the bubble rises. .………………………………………………………………………….……….………… .……………………………………………………………………………….………… [2] (c) State and explain how the pressure of the air bubble differs if the gas does not behave as an ideal gas. ………….…...………………………………………………………………………………….... ………………………………………………………………………………………………… [2] [Total: 11]

9 © DHS 2024 9749/03 [Turn over 4 Mr Tan is studying a water wave in which all the wavefronts are parallel to one another. The variation with time t of the displacement x of a particular particle in the wave is shown in Fig. 4.1. The distance d of the oscillating particles from the source of the waves is measured. At a particular time, the variation of the displacement x with this distance d is shown in Fig. 4.2. (a) (i) Use Figs. 4.1 and 4.2 to state and explain whether the wave is losing power as it moves away from the source. …...…………………………………………………………………………………………. …...…………………………………………………………………………………………. …...…………………………………………………………………………………………. …...……………………………………………………………………………………… [2] Fig. 4.1 Fig. 4.2

10 © DHS 2024 9749/03 (ii) Determine the ratio source from cm 6.0 waveofintensity source at wavethe ofintensity ratio = ………………… [2] (b) A beam of plane -polarised light of intensity Io is incident on an ideal polariser. T