SAJC Prelim (H2) P2 2023

1 SAJC 2023 Preliminary Examination / 9749 [Turn Over Class Index Number Name 22S ST. ANDREW’S JUNIOR COLLEGE JC 2 2023 Preliminary Examination PHYSICS, Higher 2 9749/02 Paper 2 Structured Questions 12th September 2023 2 hours Candidates answer on the Question Paper. No additional materials are required. READ THESE INSTRUCTIONS FIRST Write your name, index number and Civics Group on all the work you hand in. Write in dark blue or black pen. You may use a soft pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. 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. For Examiner’s Use 1 / 12 2 / 12 3 / 13 4 / 7 5 / 16 6 / 20 Total / 80 This document consists of 24 printed pages including this page.

2 SAJC 2023 Preliminary Examination / 9749 Data speed of light in free space, c = 3.00 x 108 m s-1 permeability of free space, o = 4  x 10-7 H m-1 permittivity of free space, o = 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 Formulae uniformly accelerated motion, s = u t + ½ a t2 v2 = u2 + 2 a s work done on/by a gas, W = p V hydrostatic pressure, p =  g h gravitational potential,  = r Gm− temperature, T / K = T / oC + 273.15 pressure of an ideal gas, p = 1 3 Nm v 〈c2〉 mean translational kinetic energy of an ideal gas molecule, E = 2 3 kT displacement of particle in s.h.m., x = xo sin  t velocity of particle in s.h.m., v = v0 cos  t v =   22 0 xx − electric current I = Anvq resistors in series, R = R1 + R2 + ... resistors in parallel, 1 / R = 1 / R1 + 1 / R2 + ... electric potential, V = r Q 04 alternating current/voltage, x = xo sin  t magnetic flux density due to a long straight wire, B = μ0I 2πd magnetic flux density due to a flat circular coil, B = μ0NI 2r magnetic flux density due to a long solenoid, B = μ0nI radioactive decay, x = xo exp (- t) decay constant,  = 2/1 2ln t

3 SAJC 2023 Preliminary Examination / 9749 [Turn Over Answer all questions in the spaces provided. 1 (a) Define gravitational potential energy of a mass at a point. ……………………………………………………………………………………………………. ………………………………………………………………………………………………… [1] (b) A spherical planet has mass M and radius R. The planet may be considered to have all its mass concentrated at its centre. A rocket is launched from the surface of the planet such that the rocket moves radially away from the planet. The rocket engines are stopped when the rocket is at a height R above the surface of the planet. The mass of the rocket, after its engines have been stopped, is m. (i) Show that, for the rocket to travel from a height R to a height 2R above the planet’s surface, the change Δ U in magnitude of the gravitational potential energy of the rocket is given by the expression ΔU = GMm 6R . [2]

4 SAJC 2023 Preliminary Examination / 9749 (ii) During the ascent from a height R to a height 2R, the speed of the rocket changes from 7600 m s-1 to 7320 m s-1. The planet has a radius of 3.40 x 106 m. Determine a value for the mass M of the planet. M = ………………………….. kg [3] (iii) State two assumptions made in the determination in (b)(ii). ……………………………………………………….…………………………………….. ……………………………………………………….…………………………………….. ……………………………………………………….………………………………… [2] (c) (i) A satellite is orbiting in a geostationary orbit around the Earth of mass M. Explain why the satellite must be above the equator. ……………………………………………………….…………………………………….. ……………………………………………………….…………………………………….. ……………………………………………………….…………………………………….. ……………………………………………………….………………………………… [2]

5 SAJC 2023 Preliminary Examination / 9749 [Turn Over (ii) Deduce the distance r of the geostationary satellite from the centre of the Earth in terms of M. Explain your working clearly. [2]

6 SAJC 2023 Preliminary Examination / 9749 2 (a) State what is meant by specific latent heat of vaporization. ……………………………………………………………………………………………………. ……………………………………………………………………………………………………. ………………………………………………………………………………………………… [1] (b) When a liquid is boiling, thermal energy must be supplied in order to maintain a constant temperature. State two processes for which thermal energy is required during boiling. 1. ………………………………………………………………………………………………… ………………………………………………………………………………………………… 2. ………………………………………………………………………………………………… ………………………………………………………………………………………………… [2] (c) A styrofoam container of negligible heat capacity contains 900 g of water at 85 °C. 100 g of ice at 0 °C was then added to water. With reference to the data below, (i) Calculate the equilibrium temperature of the mixture. temperature = ………………………….. °C [2] (ii) Explain why exposure to steam at 100 °C produces a more severe burn than exposure to the same amount of hot water at 100 °C. ……………………………………………………………………………………………... ……………………………………………………………………………………………... …………………………………………………………………………………………. [1] Specific latent heat of fusion of water / J kg–1 3.34 × 105 Specific heat capacity of water / J kg–1 K–1 4200 Specific latent heat of vaporisation of water / J kg–1 2.26 × 106

7 SAJC 2023 Preliminary Examination / 9749 [Turn Over (d) A fixed mass of an ideal gas undergoes the cycle of changes XYZX as shown in Fig. 2.1. Referring to Fig. 2.1, volume / 10-4 m3 2 4 6 8 10 pressure / 105 Pa Fig. 2.1 (i) determine the work done on the gas in the process XY, work done on gas = ………………………….. J [2] (ii) explain why the process ZX must involve heat transfer. ……………………………………………………….…………………………………….. ……………………………………………………….…………………………………….. ……………………………………………………….………………………………… [2] (iii) On Fig. 2.1, mark an ‘x’ at the point where the gas has approximately the highest temperature. Explain how you arrived at the answer. …………….…………….…………….…………….…………….…………….………… …………….…………….…………….…………….…………….…………….…….. [2] 6 8 10 12 Y Z X

8 SAJC 2023 Preliminary Examination / 9749 3 (a) The apparatus illustrated in Fig 3.1 is used to demonstrate two-source interference using light. Fig. 3.1 (not drawn to scale) The separation of the two slits in the double slit arrangement is a and the interference fringes are viewed on a screen at a distance D from the double sli t. When light of wavelength  is incident on the double slit, the separation of the bright fr