(EJC) 2024 J2 H2 PRELIM QP P3

©EJC 2024 9749/J2H2PRELIM/2024 [Turn over EUNOIA JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATIONS 2024 General Certificate of Education Advanced Level Higher 2 CANDIDATE NAME CIVICS GROUP 2 3 - REGISTRATION NUMBER PHYSICS Longer Structured Questions 9749/03 September 2024 2 hours READ THESE INSTRUCTIONS FIRST Write your name, civics group and registration number on all the work you hand in. The use of an approved scientific calculator is expected where appropriate. Section A Answer all questions. Section B Answer one question only. 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 paper clips, highlighters, glue or correction fluid. The number of marks is given in brackets [ ] at the end of each question or part question. This document consists of 24 printed pages. For Examiner’s Use Q1 7 Q2 8 Q3 7 Q4 10 Q5 10 Q6 10 Q7 8 Q8 20 Q9 20 s.f. P3 Total 80

2 ©EJC 2024 9749/J2H2PRELIM/2024 Data speed of light in free space, ( )( ) 81 71 0 12 1 0 91 19 34 27 31 e 27 p 11 23 1 A 23 1 10 m s 10 H m 10 F m 10 F m 10 C 6 63 10 J s 1 3 00 4 8 85 1 36 1 60 9 11 1 67 66 10 kg 10 kg 10 kg J K mol 6 02 10 8 31 1 38 mol 10 J K c. . / e h. u. m m . . . R. N k . . G    − −− −− −− − − − − − −− − −−      = = = =   = = = = = = = =  11 2 2 2 10 N m kg m 67 81 s 6 9 . g. −− − = =  permeability of free space, permittivity of free space, elementary charge, the Planck constant, unified atomic mass constant, rest mass of electron, rest mass of proton, molar gas constant, the Avogadro constant, the Boltzmann constant, gravitational constant, acceleration of free fall,

3 ©EJC 2024 9749/J2H2PRELIM/2024 [Turn over Formulae uniformly accelerated motion, ( ) ( ) 2 22 2 0 0 22 0 12 12 0 0 0 0 0 0 1 2 1 2 2 / K / C 273 15 1 3 3 2 sin cos 1 1 1 4 sin 2 2 exp ln2 at u as V p gh Gm r T T . Nmpc V kT x x t v v t xx R / R / R / R QV r x x t B d NB r s ut v Wp t E Bn t Anvq RR xx              =+  = =− =  + = = = = − ++ = + + = = = = = − = =+ = = = = = I I I I work done on/by a gas, hydrostatic pressure, gravitational potential, temperature, pressure of an ideal gas, mean translational kinetic energy of an ideal gas molecule 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

4 ©EJC 2024 9749/J2H2PRELIM/2024 Section A Answer all questions in this section in the spaces provided. 1 Fig. 1.1 shows a simple pendulum consisting of a mass m attached to a light inextensible string of length L. The pendulum is secured to a fixed point and made to undergo oscillations when displaced sideways by a small angle θ. Fig. 1.1 (not to scale) The following equation describes the period T of the oscillation: LT g=22 4 where g is the acceleration of free fall. (a) Given L = 50.0 ± 0.2 cm and g = 9.8 ± 0.1 m s−2, find T with its associated uncertainty. T = ………………… ± ………………… s [4] m L 

5 ©EJC 2024 9749/J2H2PRELIM/2024 [Turn over (b) A student measures the period of an oscillation using two methods. In the first method, he measures the period of one oscillation directly. In the second method, he measures the total time for 20 oscillations, and then divides the total time by 20 to obtain the period for one oscillation. (i) The student took three readings each using the two methods. Using suitable calculation, predict which set of data will be more precise. ………………………………………………………………………………………………. ………………………………………………………………………………………………. …………………………………………………………………………………………… [2] (ii) In reality, the student mistook the time for half an oscillation to be one period. Explain whether calculating the period by dividing the total time taken for multiple oscillations by the number of oscillations will reduce this type of error committed. ………………………………………………………………………………………………. …………………………………………………………………………………………… [1] [Total: 7]

6 ©EJC 2024 9749/J2H2PRELIM/2024 2 (a) Define acceleration. …………………………………………………………………………………………………....... …………………………………………………………………………………………………...[1] (b) An object is released from rest in a viscous fluid. Fig. 2.1 shows the variation with time t of the acceleration a of the object as it falls in the fluid. (i) Explain why the acceleration of the object decreases with time. …………………………………………………………………………………………....... …………………………………………………………………………………………....... ………………………………………………………………………………………….. [2] (ii) Explain why the initial value of the acceleration is 9.81 m s−2. …………………………………………………………………………………………....... ………………………………………………………………………………………….. [1] 0 2 4 6 8 10 0 2 4 6 8 Fig. 2.1 a / m s–2 t / s 10 8 6 4 2 0 0 2 4 6 8

7 ©EJC 2024 9749/J2H2PRELIM/2024 [Turn over (iii) Use Fig. 2.1 to estimate the speed of the object when its acceleration is zero. Explain your working clearly. speed = ……………………… m s–1 [2] (iv) In Fig. 2.2, sketch the variation of the displacement s of the object with time t, from t = 0 s to t = 8 s. There is no need to label the displacement axis. [2] [Total: 8] s / m t / s 0 2 4 6 8 Fig. 2.2 0

8 ©EJC 2024 9749/J2H2PRELIM/2024 3 A 12 V cell of internal resistance 30 , a light-dependent resistor (LDR) and a 600  resistor are connected as shown in Fig. 3.1. Fig. 3.1 (a) In conditions of low intensity light, the resistance of the LDR is 3000 . (i) Show that the current through the LDR is 3.8 mA. [3] (ii) Hence or otherwise, determine the power dissipated in the LDR. power = ……………………… W [1] (b) The LDR is exposed to bright sunlight. State and explain what would happen to the terminal potential difference. …………………………………..………………………………………………………………… …………………………………..………………………………………………………………… …………………………………..………………………………………………………………… …………………………………..………………………………………………………………… ………………………………..……………………………………...…………………...…… [3] [Total: 7] 12 V 30  600 

9 ©EJC 2024 9749/J2H2PRELIM/2024 [Turn over 4 (a) Define magnetic flux density. ……………………………………………………………………………………………………… ...…………………………………………………………………………………………………[1] (b) Fig. 4.1 shows a loudspeaker magnet consisting of a circular north pole N and a cylindrical south pole S. Part C is a moving coil that coils around S, and it is attached to a spring balance, which is attached to an adjustable support T. Current was passed through the coil C, and the adjustable support T was then adjusted so that the coil C was restored to its original position. The readings F on the balance for various currents I are recorded in Table 4.1 below. Table 4.1 I / A 0.20 0.41 0.60 0.81 F / N 1.50 2.02 2.48 3.05 (i) The direction of current flowing in the coil is indicated in Fig. 4.1(b) . Draw two arrows, one each at positions A and B, to indicate the direction of the magnetic force acting on the coil. Explain your answer. ……………………………………………………………………………………………… ……………………………………………………………………………………………… ……………………………………………………………………………………………… ………………………………………………………………………………………… [3] Fig. 4.1 (b) side view x N N x S C x A