RI 2020 Promo H2 Physics QP

© Raffles Institution [Turn over RAFFLES INSTITUTION 2020 YEAR 5 PROMOTION EXAMINATION 2 October 2020 Time: 2 hr 30 min H2 PHYSICS RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFL ES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFL ES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFL ES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFL ES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFLES INSTITUTION RAFFL ES INSTITUTION Section A INSTRUCTIONS TO CANDIDATES There are 3 sections in this paper. Section A consists of 15 multiple-choice questions. For each question, there are four possible answers A, B, C and D. Choose the one you consider correct and record your choice in soft pencil on the separate Optical Mark Sheet. You are advised to attempt Section A first . The Optical Mark Sheets will be collected after the first 30 minutes. Section B consists of 5 structured questions. You are to write your answers in the spaces provided. Section C consists of 1 long structured question and 1 data analysis question. You are to write your answers in the spaces provided. Attempt ALL questions in Sections A, B and C. There are 8 printed pages, inclusive of the cover page and data & formulae page, in this booklet.

2 © Raffles Institution Data speed of light in free space c = 3.00 × 108 m s−1 permeability of free space 0µ = 4π × 10−7 H m−1 permittivity of free space 0ε = 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 Formulae uniformly accelerated motion s = 21 2ut at+ 2v = 2 2u as+ work done on/by a gas W = pV∆ hydrostatic pressure p = ρgh gravitational potential φ = 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 sinxt ω velocity of particle in s.h.m. v = 0 cosvt ω 22 0xxω= ±− electric current I = Anvq resistors in series R = 12 RR++  resistors in parallel 1/R = 1211 RR++  electric potential V = 4 Q rε0π alternating current/voltage x = 0 sinxt ω magnetic flux density due to a long straight wire B = 0 2 d µ π I magnetic flux density due to a flat circular coil B = 0 2 N r µ I magnetic flux density due to a long solenoid B = 0nµ I radioactive decay x = ( )0 expxt λ− decay constant λ = 12ln2 t

3 © Raffles Institution [Turn over 1 The energy E of a photon of light of frequency f is given by the equation E hf= where h is the Planck constant. What are the base units of h? A 2kg m s− B 23kg m s − C 22kg m s − D 21kg m s − 2 Each of the following diagrams shows four vectors of equal magnitude. In which diagram is the magnitude of the resultant vector different from the rest? A B C D 3 Ball P is dropped from rest at a height of 25 m. At the same time, ball Q is thrown vertically upwards from the ground directly below Ball P. They collide after 1.5 s. What is the initial speed of ball Q? A 2.0 m s–1 B 15 m s–1 C 17 m s–1 D 31 m s–1

4 © Raffles Institution F / N t / s 4 − 2 2 1 2 3 4 5 6 0 4 The graph shows the variation with time t of force F acting on a 4.0 kg mass moving in a straight line. The velocity of the mass at time t = 1 s is 1.8 m s−1. What is the velocity of the mass at t = 5 s? A 1.0 m s−1 B 2.6 m s−1 C 2.8 m s−1 D 3.8 m s−1 5 Which of the following statements is correct? A A floating object in equilibrium displaces an amount of fluid that is of the same volume as the object. B A floating object in equilibrium displaces an amount of fluid that is of the same mass as the object. C When no net force acts on a partially submerged object, it must be in equilibrium. D When an object is sinking in an incompressible fluid, the upthrust it experiences increases as it sinks.

5 © Raffles Institution [Turn over 6 A constant force F is applied to an object that is initially at rest on a large smooth surface. Which graph shows the variation with time t of the power supplied P? A B C D 7 A smooth hemispherical bowl is placed on a horizontal surface. A marble undergoes horizontal uniform circular motion in the bowl. The forces acting on the marble are its weight and the normal contact force due to the bowl. Which of the following statements is true? A The magnitude of the weight is always larger than that of the normal contact force. B The magnitude of the normal contact force is always larger than that of the weight. C The magnitudes of the weight and normal contact force are the same. D The angle α determines whether the magnitude of the weight or that of the normal contact force is larger. P P P P marble bowl normal contact force weight α trajectory of the marble t 0 object smooth surface F t 0 t 0 t 0

6 © Raffles Institution 8 Two identical satellites A and B orbit around the Earth in circular orbits of radii r1 and r2 respectively. What is the ratio kinetic energy of satellite A kinetic energy of satellite B ? A 1 2 r r B 2 1 r r C 1 2 r r D 2 1 r r 9 An astronaut landed on a planet of mass ten times and radius two times that of the Earth. Which of the following statements about the astronaut is correct? A The weight of the astronaut on the planet is 2.5 times his weight on Earth. B The weight of the astronaut on the planet is 5 times his weight on Earth. C The maximum height reached by the astronaut when he jumps vertically on the planet is 0.2 times of that on the Earth. D The maximum height reached by the astronaut when he jumps vertically on the planet is 2.5 times of that on the Earth. 10 A block of mass m, attached to two walls by two springs under tension, is displaced to the right by 2.0 cm as shown. After being released from rest, it oscillates in simple harmonic motion at an angular frequency ω. The effective force constant of the springs is mω2. What is the shortest distance that the block moves from the point of release such that its potential energy is the same as its kinetic energy? A 0.6 cm B 1.0 cm C 1.4 cm D 2.0 cm wall wall 2.0 cm block equilibrium position

7 © Raffles Institution [Turn over 11 The variation with frequency f of the amplitude xo of the forced oscillations of a spring mass system is as shown. Which of the following statements is not correct? A At 12 Hz, the rate of gain of energy is equal to the rate of loss of energy by the system. B Increased damping reduces the sharpness of the resonance peak. C Decreased damping lowers the frequency at which the system responds with the highest amplitude. D Damping decreases the am