2026 SAJC H2 Physics 9478 Prelim P2

1 SAJC 2026 Preliminary Examination / 9478 [Turn over Class Index Number Name 25S ST. ANDREW’S JUNIOR COLLEGE JC 2 2026 Preliminary Examination PHYSICS, Higher 2 9478/02 Paper 2 Structured Questions 2nd September 2026 2 hours You must answer on the question paper. No additional materials are needed. INSTRUCTIONS ● Answer all questions. ● Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs. ● Write your name, index number and class in the boxes at the top of the page. ● Write your answer to each question in the space provided. ● Do not use an erasable pen. Do not use correction fluid or tape. ● You may use an approved calculator. INFORMATION ● The total mark for this paper is 75. ● The number of marks for each question or part question is shown in brackets [ ]. For Examiner’s Use 1 / 9 2 / 10 3 / 6 4 / 13 5 / 8 6 / 9 7 / 20 Total / 75 This document has 25 pages. Any blank pages are indicated.

2 SAJC 2026 Preliminary Examination / 9478 [Turn over 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 4𝜋𝜀𝑜 = 8.99 x 109 m F-1) elementary charge e = 1.60 x 10-19 C 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 Avogadro constant NA = 6.02 x 1023 mol-1 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 + 1 2 a t2 v2 = u2 + 2 a s work done on / by a gas W = p V pressure p = F A gravitational potential  = − Gm r 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 particle E = 2 3 kT

3 SAJC 2026 Preliminary Examination / 9478 [Turn over displacement of particle in s.h.m. x = xo sin  t velocity of particle in s.h.m. v = v0 cos  t =   22 0 xx − electric current I = nAvq resistors in series R = R1 + R2 + ... resistors in parallel 1 / R = 1 / R1 + 1 / R2 + ... capacitors in series 1 / C = 1 / C1 + 1 / C2 + ... capacitors in parallel C = C1 + C2 + ... energy in a capacitor U = 1 2 QV = 1 2 Q2 C = 1 2 C V2 charging a capacitor Q = Qo[1- e − t τ] discharging a capacitor Q = Qo e − t τ RC time constant  = RC electric potential V = Q 4𝜋ε0r 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 energy states for quantum particle in a box En= h2 8mL2 n2 radioactive decay x = xo e - t radioactive decay constant  = ln 2 t1/2

4 SAJC 2026 Preliminary Examination / 9478 [Turn over Answer all the questions in the spaces provided. 1 (a) Define acceleration. ………………….…….…….…….…….…….…….…….…….…….…….…….…….……………. ……..…….…….…….…….…….…….…….…….…….…….…….…….…….……………..… [1] (b) A diver stands on a platform above a pool of water, as shown in Fig. 1.1. Fig. 1.1 (not to scale) When the diver is on the platform his centre of gravity is at a vertical height of 9.0 m above the surface of the water. The diver jumps from the platform with a velocity of 5.9 m s-1 at an angle of 60° to the horizontal. Air resistance is negligible. When the diver hits the surface of the water, his centre of gravity is at a vertical height of 1.2 m above the surface of the water.

5 SAJC 2026 Preliminary Examination / 9478 [Turn over Calculate the speed of the diver at the instant he hits the surface of the water. speed = ................................................ m s-1 [3] (c) After entering the water, the 78 kg diver experiences an upward drag force of 950 N and a buoyant force of 740 N at a particular instant. (i) Calculate the magnitude of the resultant force and the acceleration of the diver at this instant. resultant force = ............................................... N acceleration = .......................................... m s-2 [3] (ii) Describe and explain the variation of the drag force acting on the diver in the water as he moves downwards. …….…….…….…….…….…….…….…….…….…….…….…….…….…….…….….. …….…….…….…….…….…….…….…….…….…….…….…….…….…….…….….. …….…….…….…….…….…….…….…….…….…….…….…….…….…….…….….. …….…….…….…….…….…….…….…….…….…….…….…….…….…….…….. [2]

6 SAJC 2026 Preliminary Examination / 9478 [Turn over 2 A steel ball is placed on the inside surface of a hollow circular cone. The ball moves in a horizontal circle at constant speed, as shown in Fig. 2.1. Fig. 2.1 The angle of the side of the cone to the horizontal is 52°. There is no friction between the ball and the cone. (a) Fig. 2.2 shows a cross‑section through the cone and the steel ball. Fig. 2.2 On Fig. 2.2, draw labelled arrows to show the two forces acting on the ball. [2]

7 SAJC 2026 Preliminary Examination / 9478 [Turn over (b) Describe how the forces acting on the ball cause its acceleration to be centripetal. …….………………….…….…….…….…….…….…….…….…….…….…….…….…….….. …….………………….…….…….…….…….…….…….…….…….…….…….…….…….….. ………………….…….…….…….…….…….…….…….…….…….…….…….…….…….….. ……..…….…….…….…….…….…….…….…….…….…….…….…….…….…….…….. [2] (c) The ball moves in a circle of radius 0.15 m. Show that the speed of the ball is 1.4 m s–1. [3] (d) Calculate the angular speed ω of the ball. ω = .............................................. rad s–1 [1] (e) The speed of the ball is increased. State and e xplain what happens to the radius of the circular path of the ball. ……………………………………………………………………………………………………..…. …………………………………………………………………………………………………..……. …………………………………………………………………………………………….……… [2]

8 SAJC 2026 Preliminary Examination / 9478 [Turn over 3 A sample of gas contains a fixed amount of gas. The gas has pressure p, volume V and thermodynamic temperature T. Fig. 3.1 shows the variation of pV with kT for the sample, where k is the Boltzmann constant. Fig. 3.1 (a) (i) Explain what is indicated about the nature of the gas from the variation shown in Fig. 3.1. …….…….…….…….…….…….…….…….…….…….…….…….…….…….……….... [1] (ii) Determine the amount n of molecules of the gas in the sample. n = …………………… mol [2]

9 SAJC 2026 Preliminary Examination / 9478 [Turn over (b) The root-mean-square (r.m.s.) speed of the molecules of the gas is 1900 m s–1 when pV is equal to 270 J. Determine the mass of one molecule of the gas. mass = ...................................................... u [3]

10 SAJC 2026 Preliminary Examination / 9478 [Turn over 4 (a) Define electric potential at a point. ……………...…………..……………………………………..…………………………………… ……………...…………..……………………………………..…………………………....……… ……