2019 RI Prelims Paper 3 Sect A QP

This document consists of 16 printed pages. © Raffles Institution [Turn over Centre Number Index Number Name Class S3016 RAFFLES INSTITUTION 2019 Preliminary Examination PHYSICS Higher 2 Paper 3 Longer Structured Questions 9749/03 27 September 2019 2 hours Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your index number, name and class in the spaces at the top of this page. Write in dark blue or black pen in the spaces provided in this booklet. You may use a 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 and circle the question number on the cover page. You are advised to spend one and 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 booklet only contains Section A. For Examiner’s Use Section A 1 / 7 2 / 10 3 / 7 4 / 10 5 / 10 6 / 9 7 / 7 Section B (circle 1 question) 8 / 20 9 / 20 Deduction Total / 80

2 © Raffles Institution 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 × 10 23 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 s  21 2ut at 2v  2 2ua s work done on/by a gas W  p V hydrostatic pressure p  ρgh gravitational potential   Gm r temperature T/K  / C 273.15T  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  0 sinx t velocity of particle in s.h.m. v  0 cosvt  22 0x x  electric current I  Anvq resistors in series R  12 ...RR resistors in parallel 1/ R  1211 . . .RR electric potential V  4 Q r alternating current/voltage x  0 sinx t magnetic flux density due to a long straight wire B  0 2 d   I magnetic flux density due to a flat circular coil B  0 2 N r  I magnetic flux density due to a long solenoid B  0n I radioactive decay x   0 expxt  decay constant   1 2 ln2 t

3 © Raffles Institution [Turn over Section A Answer all the questions in the spaces provided. 1 (a) Define moment of a force about a point. [2] (b) Fig. 1.1 shows a force diagram that represent s a load that is being lifted by the boom of a mobile crane. The weight of the mobile crane is 3.5  10 5 N, the weight of the boom is 5.0  104 N and the weight of the load is W. A counterweight of 8.4  104 N is placed onto the crane to allow heavier loads to be lifted. (i) The mobile crane will pivot about a point if the load is too heavy. On Fig. 1.1, mark this point and label it P. [1] (ii) Explain wh y the addition of a counterweight enables the crane to lift heavier loads. [2] (iii) Use the principle of moments to determine the maximum weight of the load that can be lifted by the crane at a constant speed. W = N [2] Fig. 1.1 3.5  105 N W load 3.2 m 20 m counterweight 8.4  104 N 3.2 m 5.0  104 N 7.6 m boom

4 © Raffles Institution 2 Fig 2.1 shows the variation with the distance d from the centre of the Moon of the gravitational potential  between the surface of the Moon and the surface of the Earth. Point P is on the surface of the Moon. Point Q, at a distance x from the center of the Earth, is where the gravitational potential due to the Earth and the Moon is the highest. mass of Moon = 7.4  10 22 kg mass of Earth = 6.0  1024 kg Earth-Moon distance = 3.8  108 m Fig. 2.1 (not drawn to scale) (a) State what is meant by gravitational potential at a point. [2] (b) Show that x is approximately 3.4  108 m. x = m [2] Q x  / J kg1 d / m Earth Moon  3.9  106  6.23  107  1.3  106 P

5 © Raffles Institution [Turn over (c) A research company plans to launch a satellite of 520 kg that orbits around the Earth to observe the Moon. In order to observe the Moon continuously, the satellite has an orbital period of 27 days such that it is always in between the Earth and the Moon as shown in Fig. 2.2. Fig. 2.2 (not drawn to scale) (i) When the satellite is in orbit, the resultant force acting on the satellite due to the Moon and the Earth is 1.22 N. Show that the distance of the satellite from the Earth is approximately 3.2  10 8 m. [2] (ii) Hence, determine the gravitational potential at the location of the satellite due to the Earth and the Moon. gravitational potential = J kg 1 [3] 3.8  108 m Earth Moon satellite

6 © Raffles Institution (d) An instrument is to be launched from the satellite to the Moon while it is in orbit. A student claims that the minimum energy required to send the instrument to the Moon is the product of the mass of the instrument and the difference in gravitational potential on the surface of the Moon and at the position of the satellite. Comment on the statement. [1]

7 © Raffles Institution [Turn over 3 (a) State the first law of thermodynamics. [2] (b) A fixed mass of an ideal gas undergoes a cycle of changes ABCA, as shown in Fig. 3.1. (i) Calculate the work done by the gas during the change C to A. work done b y the gas = J [2] (ii) Some energy changes during one cycle ABCA are shown in Fig. 3.2. change work done on gas / J heat supplied to gas / J increase in internal energy / J A to B 310 0 B to C  610 C to A Use your answer in (i) to complete Fig. 3.2. [3] Pressure / 105 N m2 Volume / 103 m3 3.03 1.00 2.00 4.00 B C A Fig. 3.1 Fig. 3.2

8 © Raffles Institution 4 (a) (i) State the conditions required for the formation of a stationary wave. [2] (b) Fig. 4.1 shows two small and identical microwave emitters S1 and S2 placed 0.12 m apart in a wide open space. The emitters are in phase and emit microwaves of wavelength 0.040 m uniformly in all directions. (i) On Fig. 4.1, sketch the stationary wa ve pattern formed in the space between S 1 and S2. Mark all the positions of the displacement nodes (use the letter N) and the displacement antinodes (use the letter A). [2] (ii) A microwave receiver is now placed at the point M, 0.18 m to the right of S 2, and along the line S1S2 as shown in Fig. 4.2. path of receiver M S1 S2 0.18 m 0.12 m receiver Fig. 4.2 (not drawn to scale) S1 S2 0.12 m Fig. 4.1

9 © Raffles Institution [Turn over 1. State and explain whether the intensity of t