2025 NYJC H2 Phy 9749 P2

NYJC 2025 9749/02/J2Prelim/25 [Turn over NANYANG JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION Higher 2 CANDIDATE NAME CLASS TUTOR’S NAME CENTRE NUMBER S INDEX NUMBER PHYSICS 9749/02 Paper 2 Structured Questions 15 September 2025 2 hours Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your name, class, Centre number and index number in the spaces at the top of this page. Write in dark blue or black pen on both sides of the paper. You may use a HB pencil for any diagrams, graphs. Do not use staples, paper clips, 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 / 7 2 / 7 3 / 11 4 / 11 5 / 8 6 / 7 7 / 9 8 / 20 Total / 80 This document consists of 24 printed pages. H

2 NYJC 2025 9749/02/J2Prelim/25 Data speed of light in free space c = 3.00 × 108 m s−1 permeability of free space  = 4 × 10−7 H m−1 permittivity of free space  = 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 Formulae uniformly accelerated motion 21 2s ut at=+ 22 2v u as=+ work done on / by a gas W p V= hydrostatic pressure p gh= gravitational potential /Gm r =− temperature / K / C 273.15TT =  + pressure of an ideal gas 21 3 Nmpc V=   mean translational kinetic energy of an ideal molecule 3 2E kT= displacement of particle in s.h.m. 0 sinx x t = velocity of particle in s.h.m. 0 cosv v t = 22 0xx=  − electric current =I Anvq resistors in series 12 . . .R R R= + + resistors in parallel 121/ 1/ 1/ . . .R R R= + + electric potential 04 QV r= alternating current/voltage 0 sinx x t = magnetic flux density due to a long straight wire  = 0 2 IB d magnetic flux density due to a flat circular coil = 0 2 NIB r magnetic flux density due to a long solenoid = 0B nI radioactive decay 0 exp( )x x t =− decay constant 1 2 ln2 t =

3 NYJC 2025 9749/02/J2Prelim/25 [Turn over Answer all the questions in the spaces provided. 1 The rate of heat flow through a rod due to conduction is given by Fourier’s Law: = ()Q CA T tL where A is the cross-sectional area of the material, L is the length of the material, T is the temperature difference across the length of the material, and C is a constant. (a) Determine the SI base units of C. SI base units = [2]

4 NYJC 2025 9749/02/J2Prelim/25 (b) An experiment is conducted to determine the value of C. Using copper rod of diameter 0.80 cm but different length, and two ends of the rod are maintained at pure ice point and steam point, the rate of flow of thermal energy was measured using a heat flux sensor. A graph of how Q t varies with 1 L is plotted, as shown in Fig. 1.1. Fig. 1.1 (i) State the feature of the graph that indicates the presence of systematic error in the experiment. ………………………………………………………………………………………….….. ………………………………………………………………………………….…..……[1] 0.05 0.10 0.15 0.20 0.25 0.30 / W 10 20 30 40 50 60 / cm-1 0

5 NYJC 2025 9749/02/J2Prelim/25 [Turn over (ii) Calculate the value of C, in SI units, from Fig. 1.1. value of C = ………..…………. SI base units [3] (iii) With reference to Fig. 1.1 and (b)(i), state and explain whether the accuracy of C is affected by the presence of systematic error in the experiment. ………………………………………………………………………………………….….. ………………………………………………………………………………………….….. ………………………………………………………………………………………….….. ………………………………………………………………………………….………..[1] [Total: 7]

6 NYJC 2025 9749/02/J2Prelim/25 2 (a) State the principle of conservation of momentum. ………………………………………………………………………………………….……………. ………………………………………………………………………………………….……………. ………………………………………………………………………………………….……………. ………………………………………………………………………………….……………….....[1] (b) Fig. 2.1 shows a metal bullet of mass 2.0 g fired horizontally into a block of wood of mass 600 g. The block is suspended from strings so that it is free to move in the vertical plane. The bullet hits and becomes embedded in the block. The block and bullet rise together through a vertical distance of 8.6 cm. Fig. 2.1 (i) Show that the speed of the block and bullet as they just move off together is 1.3 m s-1. [2]

7 NYJC 2025 9749/02/J2Prelim/25 [Turn over (ii) Using (a) and (b)(i), determine the speed of the bullet before the impact with the block. speed = m s−1 [2] (iii) A rubber bullet of the same mass hits the block with the same speed calculated in (ii) and rebounds in the opposite direction. State and explain whether the block will reach a maximum height of greater or less than 8.6 cm. [2] [Total : 7]

8 NYJC 2025 9749/02/J2Prelim/25 3 A steel sphere of mass 0.30 kg is suspended in equilibrium from a vertical spring. The centre of the sphere is 8.5 cm from the top of the spring, as shown in Fig. 3.1. Fig. 3.1 The sphere is now set in motion so that it is moving in a horizontal circle at constant speed, as shown in Fig. 3.2. Fig. 3.2 The spring stretches to a new extended length L, and the radius of the circular motion is 5.0 cm. The angle between the linear axis of the spring and the vertical is . The period of the circular motion is 0.60 s. (a) Explain, with reference to the forces acting on the sphere, why the length of the spring in Fig. 3.2 is greater than in Fig. 3.1. [3] 8.5 cm spring steel sphere, mass 0.30 kg

9 NYJC 2025 9749/02/J2Prelim/25 [Turn over (b) (i) Calculate the centripetal acceleration of the sphere. centripetal acceleration = m s−2 [1] (ii) Show that the angle  is 29°. [2] (iii) Calculate the tension in the spring in Fig. 3.2. tension in spring = N [2] (iv) Calculate the spring constant of the spring. spring constant = N m−1 [3] [Total: 11]

10 NYJC 2025 9749/02/J2Prelim/25 4 Fig. 4.1 shows a fixed mass of ideal gas in a cylinder of pressure 2.1 × 10 5 Pa, volume 4.0 × 10-4 m3 and temperature 27 °C. The gas is compressed at constant temperature along process I. Fig. 4.2 shows the variation with volume V of the pressure P of the gas. Fig. 4.2 (a) (i) With reference to Fig. 4.2, estimate the work done on the gas through process I. work done = J [3] (ii) State the first law of thermodynamics. [1] Fig. 4.1 cylinder piston gas P / × 105 Pa V / × 10-4 m-3 2.0 2.5 3.0 3.5 2.5 3.0 3.5 4.0 4.0 process I process II