HCI 2022 Prelim P3 (Section A)

This paper consists of 17 printed pages. HWA CHONG INSTITUTION JC2 Preliminary Examination Higher 2 CANDIDATE NAME CT GROUP 21S CENTRE NUMBER INDEX NUMBER PHYSICS Paper 3 Longer Structured Questions SECTION A BOOKLET Candidates answer on the Question Paper. No Additional Materials are required. 9749/03 15 September 2022 2 hours INSTRUCTIONS TO CANDIDATES Write your Centre number, index number, name and CT class clearly on all 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 staples, paperclips, highlighters, 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. Circle the question number on the cover page. You are advised to spend 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. You are reminded of the need for good English and clear presentation in your answers. For Examiner’s Use Section A 1 8 2 8 3 9 4 8 5 10 6 7 7 10 Section B 8 20 9 20 Deductions P3 80

2 © Hwa Chong Institution 9749 / 03 / C2 Preliminary Examination 2022 Data Formulae 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/(36π)) × 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 uniformly accelerated motion work done on / by a gas hydrostatic pressure gravitational potential temperature pressure of an ideal gas mean kinetic energy of a molecule of an ideal gas displacement of particle in s.h.m. velocity of particle in s.h.m. electric current resistors in series resistors in parallel electric potential alternating current / voltage magnetic flux density due to a long straight wire magnetic flux density due to a flat circular coil magnetic flux density due to a long solenoid radioactive decay decay constant s = ut + at2 v2 = u2 + 2as W = p ΔV p = ρgh T/K = T/ °C + 273.15 P = x = xo sin ωt v = vo cos ωt = I = Anvq R = R1 + R2 + . . . 1/R = 1/R1 + 1/R2 + . . . x = xo sin ω t B = μonI x = xo exp ( -λt )

3 © Hwa Chong Institution 9749 / 03 / C2 Preliminary Examination 2022 1 (a) (i) Define gravitational potential at a point. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ………………………………………………………………………………………………….. [2] (ii) Explain why gravitational potential is negative. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ………………………………………………………………………………………………….. [2]

4 © Hwa Chong Institution 9749 / 03 / C2 Preliminary Examination 2022 (b) A meteorite was observed to be traveling fast on a straight-line path inside a gravitational field. AB is a segment of this path, which occurs over a short period of time. The variation in the gravitational potential  along AB is shown in Fig 1.1 where x is the displacement of the meteorite from A. The gravitational potential reaches a maximum value when x = x0 at the point C. Fig 1.1 (i) Describe the variation in the gravitational force acting on the meteorite along the path AC. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ……………………………………………………………………………………………………….. ………………………………………………………………………………………………….. [2] (ii) On Fig 1.2, sketch the graph of the variation in the kinetic energy of the meteorite. Fig 1.2 [2] [Total: 8] A C B 0 Kinetic energy x x0

5 © Hwa Chong Institution 9749 / 03 / C2 Preliminary Examination 2022 2 Fig. 2.1 shows a cylinder containing an ideal gas of pressure P and volume V enclosed by a movable piston. The cylinder is kept submerged in a large ice-water bath maintained at 0 oC. The specific latent heat of fusion of the ice = 334 J g-1. The gas undergoes three processes in the following sequence: Process A: Gas compressed quickly from position 1 to 2 (such that there is no heat transfer to and from gas). Process B: Piston held at position 2 until the gas reaches the temperature of the ice-water bath. Process C: Piston slowly raised back to position 1. (a) The volume of gas when the piston is at position 1 and 2 are indicated as V1 and V2 respectively. The dot represents the state of gas in cylinder at the start of process A. Sketch the 3 processes on the P-V diagram in Fig. 2.2. Label the processes clearly using A, B & C. Fig. 2.2 [3] (b) Identify process B. .………….…………………………………………………………………………………………….. [1] Fig. 2.1

6 © Hwa Chong Institution 9749 / 03 / C2 Preliminary Examination 2022 (c) At the end of process C, 100 g of ice has melted. There is no heat transfer between the ice and environment. State whether net heat is transferred into or out of the gas cylinder. .………….…………………………………………………………………………………………….. [1] (d) Determine the net temperature change for the gas for one complete cycle. net temperature change = ………………….. K [1] (e) Calculate the net work done on the gas. net work done on the gas = ……………………….. J [2] [Total: 8]

7 © Hwa Chong Institution 9749 / 03 / C2 Preliminary Examination 2022 3 One end of a spring is fixed to a support. A block is attached to the other end of the spring and gently lowered to its equilibrium position, as shown in Fig. 3.1. Fig. 3.1 Using two fingers, a student pushes down sharply on the block. This immediately imparts some downward momentum to the block, causing it to oscillate. (a) Theory suggests that the vertical acceleration a of the block is related to its vertical displacement y by the expression kay m=− where k is the spring constant and m is the mass of the block. Explain why this expression leads to the conclusion that the block is performing simple harmonic motion. ………………………………………………………………………………………………………………. ………………………………………………………………………………………………………………. ………………………………………………………………………………………………………………. …………...…………………………………………………………………………………………….. [2]

8 © Hwa Chong Institution