NYJC EJC 2025 Prelim

©EJC NYJC 2025 9814/J2H3 Preliminary Examination/2025 [Turn over EUNOIA JUNIOR COLLEGE, NANYANG JUNIOR COLLEGE JC2 Preliminary Examination 2025 General Certificate of Education Advanced Level Higher 3 CANDIDATE NAME CIVICS GROUP 2 4 - REGISTRATION NUMBER PHYSICS Paper 1 9814/01 23 September 2025 3 hours Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your name, civics group and registration number on all the work you hand in. 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 paper clips, highlighters, glue or correction fluid. The use of an approved scientific calculator is expected where appropriate. Section A Answer all questions. You are advised to spend about 1 hour and 50 minutes on Section A. Section B Answer two questions only. You are advised to spend about 35 minutes on each question in 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. This document consists of 30 printed pages and 2 blank pages. For Examiner’s Use Section A 1 10 2 8 3 12 4 10 5 20 Section B 6 20 7 20 8 20 s.f. Total 100

2 ©EJC NYJC 2025 9814/J2H3 Preliminary Examination/2025 BLANK PAGE

3 ©EJC NYJC 2025 9814/J2H3 Preliminary Examination/2025 [Turn over Data speed of light in free space, c = 3.00 × 108 m s–1 permeability of free space, μo = 4π × 10–7 H m–1 permittivity of free space, εo = 8.85 × 10–12 F m–1 (1/(36 π)) × 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

4 ©EJC NYJC 2025 9814/J2H3 Preliminary Examination/2025 Formulae uniformly accelerated motion, s = ut + ½at2 v2 = u2 + 2as moment of inertia of rod through one end I = ML21 3 moment of inertia of hollow cylinder through axis I = Mr r22 12 1 ()2 + moment of inertia of solid sphere through centre I = MR22 5 moment of inertia of hollow sphere through centre I = MR22 3 work done on/by a gas, W = p ∆V hydrostatic pressure, p = ρgh gravitational potential, φ = Gm r− Kepler’s third law of planetary motion T2 = a GM π 234 temperature, T/K = T / oC + 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 = xo sin ωt velocity of particle in s.h.m. v = vo cos ωt = ( ) 22 x xo − ±ω electric current, I = Anvq 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 + …

5 ©EJC NYJC 2025 9814/J2H3 Preliminary Examination/2025 [Turn over energy in a capacitor U = CV 21 2 electric potential, V = 4 o Q rπε electric field strength due to a long straight wire E = or λ πε2 electric field strength due to a large sheet E = o σ ε2 alternating current/voltage, x = xo sin ωt magnetic flux density due to a long straight wire B = 2 o d µ π I magnetic flux density due to a flat circular coil B = 2 oN r µ I magnetic flux density due to a long solenoid B = onµ I energy in an inductor U = L 21 2 I RL series circuits 𝜏𝜏 = L R RLC series circuits (underdamped) ω = R LC L − 2 2 1 4 radioactive decay, x = xo exp (–λt) decay constant λ = 1 2 ln2 t

6 ©EJC NYJC 2025 9814/J2H3 Preliminary Examination/2025 Section A Answer all questions in this section. You are advised to spend about 1 hour 50 minutes on this section. 1 Two objects, of masses m1 and m2, and two massless springs are connected as shown in Fig. 1.1. Points A and B are the points of connection between mass m1 and the springs. Initially, the system is in equilibrium. (a) The connection between m1 and the top spring suddenly breaks at point A. (i) In terms of m1, m2 and the gravitational acceleration g, determine an expression for the acceleration immediately after the breaking for 1. m1, acceleration =…………………….. [2] 2. m2, acceleration =…………………….. [1] m1 m2 A B Fig. 1.1

7 ©EJC NYJC 2025 9814/J2H3 Preliminary Examination/2025 [Turn over 3. the centre of mass of m1 and m2. acceleration =…………………….. [2] (ii) Suggest an explanation for your value of acceleration in (i)3. ……………………………………………………………………………………………………. ………………………………………………………………………………………………….. [2] (b) The system is reconnected and in equilibrium, as shown in Fig. 1.1. The connection between m1 and the bottom spring suddenly breaks at point B, and m1 accelerates upwards while m2 accelerates downwards. (i) Without doing any calculation, state a value for the acceleration immediately after the breaking of the centre of mass of m1 and m2. acceleration = ………………… m s-2 [1] (ii) Suggest an explanation for your answer in (b)(i). …………………………………………………………………………………………………. ……………………………………………………………………………………………… [2] [Total: 10]

8 ©EJC NYJC 2025 9814/J2H3 Preliminary Examination/2025 2 Consider 3 blocks mA, mB and mC whose positions are along a straight line on a bench as shown in Fig. 2.1. m B and mC are slightly separated and initially at rest. mA is moving towards mB with an initial speed of uA. Fig. 2.1 Considering that the surfaces are frictionless and all collisions are elastic, (a) Explain what is meant by an elastic collision. ………………………………………………………………………………………………………. ………………………………………………………………………………………………………. …………………………………………………………………………………………………… [1] (b) By considering the motion of the centre of masses of suitable blocks, show that the velocity of mC after being hit by mB can be expressed as 4 ( )( + ) AB CA A BB C mmvu m mm m= + . [5]

9 ©EJC NYJC 2025 9814/J2H3 Preliminary Examination/2025 [Turn over (c) Hence, express mB in terms of mA and mC when maximum energy is transferred from mA to mC. (note: you are not required to show that it is a maximum point) m B = ………………………….. [2] [Total: 8]

10 ©EJC NYJC 2025 9814/J2H3 Preliminary Examination/2025 3 Fig. 3.1 shows a simple electric motor made up of an armature placed in between 2 permanent magnets. The region of space between the 2 magnets has a uniform magnetic flux density of 40 mT. The armature consists of a single square coil of copper wire of resistance 0.50 Ω with each side of length of 20 cm. Fig. 3.1 (a) (i) State the name of the component P and explain the purpose of P in the electric motor. ………………………………………………………………………………………………… ………………………………………………………………………………………………… …………………………………………………………………………………………….. [2] (ii) Indicate the direction of the magnetic field in the region between the 2 permanent magnets. [1] (b) (i) The armature carries a current of 0.55 A just before it starts to move from the instant as shown in Fig 3.1. Determine the magnitude of the torque acting on the armature due to the magnetic force at this instant. torque = …………………………… N m [2] component P