ASRJC 2025 H2 Physics Prelim P3

1 9749/03/ASRJC/2025PRELIM [Turn Over Name: _____________________________ ( ) Class: 25 / ______ 2025 JC2 Preliminary Examination PHYSICS Higher 2 9749/03 Paper 3 Longer Structured Questions Thursday 28 August 2025 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 provided above. 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. Section A Answer all questions. Section B Answer one question only. You are advised to spend about one and a half hours on Section A and half an hour on Section B. The number of marks is given in brackets [ ] at the end of each question or part question. This document consists of 24 printed pages and 0 blank page. For Examiner’s Use Paper 3 (80 marks) 1 2 3 4 5 6 7 8 9 Deductions Total ANDERSON SERANGOON JUNIOR COLLEGE

2 9749/03/ASRJC/2025PRELIM 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 9749/03/ASRJC/2025PRELIM [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 9749/03/ASRJC/2025PRELIM Section A Answer all the questions in this section in the spaces provided. 1 A ball is kicked from horizontal ground towards the top of a vertical wall, as shown in Fig. 1.1. Fig. 1.1 The horizontal distance between the initial position of the ball and the base of the wall is 24 m. The ball is kicked with an initial velocity v at an angle of 28° to the horizontal. The ball hits the top of the wall after a time of 1.5 s. Air resistance may be assumed to be negligible. (a) Show that the initial vertical component vY of the velocity of the ball is 8.5 m s−1. [2] (b) Calculate the time taken for the ball to reach its maximum height above the ground. time = ……………………………s [2]

5 9749/03/ASRJC/2025PRELIM [Turn Over (c) The ball is kicked at time t = 0. On Fig. 1.2, sketch the variation with time t of the vertical component vY of the velocity of the ball until it hits the wall. It may be assumed that velocity is positive when in the upwards direction. Fig. 1.2 [2] (d) A ball of greater mass is kicked with the same velocity v and at an angle of 28° to the horizontal. State and explain the effect, if any, of the increased mass on (b). Air resistance is still assumed to be negligible. …………………………………………………………………………………………….……….. ………………………………………………………………………………………….………….. …………………………………………………………………………………………….......... [1] (e) State and explain the effect of air resistance on the answer in (b). …………………………………………………………………………………………….……….. ………………………………………………………………………………………….………….. …………………………………………………………………………………………….......... [2] [Total: 9]

6 9749/03/ASRJC/2025PRELIM 2 (a) A copper wire of diameter 1.4 mm connects to the tungsten filament wire of a light bulb of diameter 0.020 mm. A current of 0.42 A flows through both of the wires. Copper has 8.0 x 1028 electrons per cubic metre and tungsten can be assumed to have 3.4 x 1028 electrons per cubic metre. (i) The filament is 2.0 m long when uncoiled and has a resistivity of 5.5 x 10-8  m. Calculate the power dissipated in the filament bulb. power dissipated = …………………………….W [2] (ii) The drift speed of electrons in the copper wire is 0.021 x 10-3 m s-1. 1. Determine the drift speed of electrons in the tungsten filament. drift speed = …………………………….m s-1 [2] 2. Explain, in microscopic terms, why the copper wire stays cool although the tungsten filament reaches a high temperature. ………………………………………………………………………………….................... ………………………………………………………………………………….................... ………………………………………………………………………………….................... ……………………………………………………………………………….………….... [2]

7 9749/03/ASRJC/2025PRELIM [Turn Over (b) A thermistor has resistance 3900  at 0 C and resistance 1250  at 30 C. The thermistor is connected into the circuit of Fig. 2.1 in order to monitor temperature changes. The battery of e.m.f. 1.50 V has negligible resistance and the voltmeter has infinite resistance. The reading on the voltmeter is 1.00 V at 0 C. (i) The temperature of the thermistor is increased to 30 C. Determine the reading on the voltmeter. reading = …………………………….V [2] (ii) The voltmeter in Fig. 2.1 is replaced with one having a resistance of 7800 . Calculate the reading on this voltmeter for the thermistor at a temperature of 0 C. reading = …………………………….V [2] [Total: 10] 1.50 V V R thermistor Fig. 2.1

8 9749/03/ASRJC/2025PRELIM 3 The Earth may be assumed to be an isolated uniform sphere with its mass M concentrated at its centre. A satellite of mass m orbits the Earth in a circular path of radius R. For the satellite in its orbit, show that (a) (i) its kinetic energy EK is given by EK= GMm 2R where G is the gravitational constant. [3] (ii) its total energy ET is given by ET= − GMm 2R [2] (b) The satellite in (a) gradually loses energy due to small resistive forces. Suggest why many such satellites eventually “burn up” in the Earth’s atmosphere. ….………………………………………………………………………………………….……….. .………………………………………………………………………………………….………….. ….………………………………………………………………………………………….……….. .………………………………………………………………………………………….………….. .………………………………………………………………………………………….………….. .………………………………………………………………………………………….………. [3]

9 9749/03/ASRJC/2025PRELIM [Turn Over (c) Polar orbiting satellites have orbits over the poles of the E