SAJC Prelim (H2) P3 2023

1 SAJC 2023 Preliminary Examination / 9749 [Turn Over Class Index Number Name 22S ST. ANDREW’S JUNIOR COLLEGE JC 2 2023 Preliminary Examination PHYSICS, Higher 2 9749/03 Paper 3 Longer Structured Questions 15th September 2023 2 hours Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your name, index number and Civics Group on all the work you hand in. Write in dark blue or black pen on both sides of the paper. 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. You are advised to spend one and a half hours on Section A and half an hour on 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 31 printed pages including this page. For Examiner’s Use Section A 1 / 11 2 / 5 3 / 10 4 / 10 5 / 12 6 / 12 Section B 7 / 20 8 / 20 Total / 80

2 SAJC 2023 Preliminary Examination / 9749 [Turn Over Data speed of light in free space c = 3.00 x 108 m s-1 permeability of free space o = 4  x 10-7 H m-1 permittivity of free space o = 8.85 x 10-12 F m-1 = (1/(36)) x 10-9 F m-1 elementary charge e = 1.60 x 10-19 C the Planck constant h = 6.63 x 10-34 J s unified atomic mass constant u = 1.66 x 10-27 kg rest mass of electron me = 9.11 x 10-31 kg rest mass of proton mp = 1.67 x 10-27 kg molar gas constant R = 8.31 J K-1 mol-1 the Avogadro constant NA = 6.02 x 1023 mol-1 the Boltzmann constant k = 1.38 x 10-23 J K-1 gravitational constant G = 6.67 x 10-11 N m2 kg-2 acceleration of free fall g = 9.81 m s-2 Formulae uniformly accelerated motion s = u t + ½ a t2 v2 = u2 + 2 a s work done on/by a gas W = p V hydrostatic pressure p =  g h gravitational potential  = r Gm− temperature T / K = T / oC + 273.15 pressure of an ideal gas p = 1 3 Nm v 〈c2〉 mean translational kinetic energy of an ideal gas molecule E = 2 3 kT displacement of particle in s.h.m. x = xo sin  t velocity of particle in s.h.m. v = v0 cos  t v =   22 0 xx − electric current I = Anvq resistors in series R = R1 + R2 + ... resistors in parallel 1 / R = 1 / R1 + 1 / R2 + ... electric potential V = r Q 04 alternating current/voltage x = xo sin  t magnetic flux density due to a long straight wire B = μ0I 2πd magnetic flux density due to a flat circular coil B = μ0NI 2r magnetic flux density due to a long solenoid B = μ0nI radioactive decay x = xo exp (- t) decay constant  = 2/1 2ln t

3 SAJC 2023 Preliminary Examination / 9749 [Turn Over Section A Answer all questions in the spaces provided 1 (a) Fig. 1.1 shows a speed -time graph for a car moving in a straight line. The graph has been divided into 5 stages A, B, C, D and E. Fig. 1.1 (i) Using Fig. 1.1, estimate the distance that the car travels during the whole 200 s. distance = …………………………… m [2] (ii) Estimate the uncertainty in your answer to (a)(i) and explain your reasoning ……………………………………………..…………………………………………………… ………………………………………………..………………………………………………… uncertainty = …………………………… m [2]

4 SAJC 2023 Preliminary Examination / 9749 [Turn Over (b) A golf ball is hit from point A on the ground and moves through the air to point B. The path of the ball is illustrated in Fig. 1.2. Fig. 1.2 (not to scale) The ground slopes downhill with constant gradient. The ball has an initial velocity of 63 m s-1 at an angle of 14° to the horizontal. The ball hits the ground at B after 4.9 s. (i) Determine the angle of the slope to the horizontal, θ. angle θ = ……………………………. ° [3] (ii) In a real situation, air resistance provides a force on the ball in the opposite direction to its motion. 1. On. Fig. 1.2, sketch a likely path of the ball hit from A when air resistance is taken into account. [1]

5 SAJC 2023 Preliminary Examination / 9749 [Turn Over 2. Give reasons for the shape you have drawn in (b)(ii)1. for the path of the ball at the start, ……………………..……………………………………………………………….. ………………………..…………………………………………………………….. ..………………………..…………………………………………………………… the position for the highest point, ……………………..……………………………………………………………….. ………………………..…………………………………………………………….. ………………………..…………………………………………………………….. the angle at which the ball hits the ground. ……………………..……………………………………………………………….. ………………………..…………………………………………………………….. ………………………..…………………………………………………………….. [3]

6 SAJC 2023 Preliminary Examination / 9749 [Turn Over 2 (a) In the circuit shown in Fig. 2.1 , the cell has an e.m.f. of 10 V and negligible internal resistance. The resistances of R1 and R2 are such that both lamps A and B are operating at their rated voltage. Fig. 2.1 Calculate the resistances of R1 and R2. R1 = ………………………….. Ω R2 = ………………………….. Ω [3] (b) In the circuit shown in Fig. 2.2, the cell has an e.m.f. of 12 V and internal resistance of 10 Ω. It is connected in series with a 7 Ω resistor and R3. Fig. 2.2 State the resistance of R3 such that there is maximum power delivered to R3. R3 = ………………………….. Ω [1] 10 V A 5.0 V, 0.50 W B 2.5 V, 0.50 W R2 R1 12 V R3 7 Ω 10 Ω

7 SAJC 2023 Preliminary Examination / 9749 [Turn Over (c) Sketch the current – voltage (I – V) characteristics of an ideal semiconductor diode. [1] I V

8 SAJC 2023 Preliminary Examination / 9749 [Turn Over 3 (a) State Coulomb’s Law. ……………………..……………………..……………………..……………………..………… ……………………..……………………..……………………..……………………..………… ……………………..……………………..……………………..……………………..……... [1] (b) Two charged metal spheres A and B are situated in a vacuum, as illustrated in Fig. 3.1. Fig. 3.1 The shortest distance between the surfaces of the spheres is 6.0 cm. A movable point P lies along the line joining the centres of the two spheres, a distance x from the surface of sphere A. The variation with distance x of the electric field E at point P is shown in Fig. 3.2. Fig. 3.2

9 SAJC 2023 Preliminary Examination / 9749 [Turn Over A proton is at rest at point P when x = 5.0 cm. Use data from Fig. 3.2 to estimate the speed of the proton at x = 3.3 cm. speed = ………………………….. m s-1 [3] (c) A charge of +5.0 C is shot through a small hole at A into a region between two parallel metal plates separated by a distance d and connected to a d.c. voltage source. One metal plate is at a potential of +100 V, and the charge emerges from another hole at B as shown in Fig. 3.3 below. Fig. 3.3 (i) The electric field between the plates is found to be 2500 V m−1. Determine the potential of the other metal plate. potential = ………………………….. V [2] θ d = 8.0 cm +100V A B v

10 SAJC 2023 Preliminary Examination / 9749 [Turn Over (ii) Sketch a possible trajectory of the charge on Fig. 3.4 when the upper plate is moved further away from the lower plate. Label this trajectory E. [1] (d) Two identical spherical drops of water, each carrying a charge of +1.0 x 10-11 C and with electric potential of 500 V on its surface, combine to form a single spherical drop. Determine the approximate potential on the surface of the new drop formed.