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 JJC 2016 8866/JC2 Prelim P2/2016 [Turn Over JURONG JUNIOR COLLEGE 2016 JC2 Preliminary Examination Name Class 16S PHYSICS Higher 1 Structured Questions Candidates answer on the Question Paper. No Additional Materials are required. 8866/02 26 Aug 2016 2 hours READ THESE INSTRUCTIONS FIRST Do not open this booklet until you are told to do so. Write your name and class in the spaces provided at the top of this page. Write in dark blue or black pen. You may use a soft pencil for any diagrams, graphs or rough working. Do not use highlighters, glue or correction fluid. Section A Answer all questions. Section B Answer any two questions. 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. For Examiner’s Use Section A 1 2 3 4 5 Section B 6 7 8 Total (This question paper consists of 25 printed pages)

 JJC 2016 8866/JC2 Prelim P2/2016 [Turn Over 2 Data speed of light in free space, c = 3.00  108 m s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 acceleration of free fall, g = 9.81 m s2 Formulae uniformly accelerated motion, s = ut + 1 2 at2 v2 = u2 + 2as work done on/by a gas, W = p V hydrostatic pressure, p = gh resistors in series, R = R1 + R2 + . . . resistors in parallel, 1/R = 1/R1 + 1/R2 + . . .

 JJC 2016 8866/JC2 Prelim P2/2016 [Turn Over 3 Section A Answer all questions in this section. 1 A small block of wood is held at a horizontal distance of 1.2 m from a metal ball as shown in Fig. 1.1 . The metal ball is fired horizontally towards the block at a speed of 8.0 m s -1. At the same instant the ball is fired, the block is released and it falls vertically under gravity. Fig. 1.1 Determine (a) the time taken for the ball to collide with the block. time = s [1] (b) the vertical distance h, travelled by the block when it collides with the ball. h = m [2]

 JJC 2016 8866/JC2 Prelim P2/2016 [Turn Over 4 (c) the speed of the ball just before it collides with the block. speed = m s -1 [2] (d) Explain why the ball will always collide with the block, even if the horizontal speed of the ball or its horizontal distance is changed. [1]

 JJC 2016 8866/JC2 Prelim P2/2016 [Turn Over 5 2 (a) Starting with the definition of work, deduce the change in the gravitational potential energy of a mass m when moved a distance h upwards near the Earth’s surface. [3] (b) Fig. 2.1 below shows a frictionless toy runway. Upon release from point A, Car 1 of mass 0.100 kg runs down a slope, and moves round the loop of radius 0.25 m, passing through points B and C. At point C, the speed of Car 1 is 1.6 m s -1. Fig. 2.1 (not drawn to scale) (i) Determine the height h at point A. h = m [2] 0.25 m

 JJC 2016 8866/JC2 Prelim P2/2016 [Turn Over 6 (ii) Car 1 moves down the loop and travels at constant speed at 3.5 m s -1 from point B towards a stationary Car 2 of mass 0.080 kg at point D. It collides head-on with Car 2 at point D. Upon collision, the two cars stick together and continue to travel towards point E until it is stopped by a spring buffer of force constant 120 N m-1. Determine the maximum compression of the spring buffer when the cars collide into it. maximum compression = m [3]

 JJC 2016 8866/JC2 Prelim P2/2016 [Turn Over 7 3 Railgun is researched as a weapon that would rely on electromagnetic forces to launch a projectile to very high kinetic energy. The railgun is basically a large electric circuit, made up of three parts: a power source, a pair of parallel conducting rails and a movable conducting projectile as shown in Fig. 3.1. When a potential difference of 1.0 kV is applied, a current I of 56 kA passes through the rail. I will flow from the power supply to the positive rail, across the projectile of negligible resistance and back to the power supply through the negative rail as shown in Fig. 3.2. Fig. 3.2 (a) With reference to Fig. 3.2, (i) show that the resistance of the rails is 0.018 Ω. [1] Fig. 3.1

 JJC 2016 8866/JC2 Prelim P2/2016 [Turn Over 8 (ii) state the direction of the resultant magnetic field (due to the current) through the projectile. [1] (b) The resultant magnetic field at the centre of the projectile is 1.12 T and is assumed to be uniform throughout the projectile. As a result, a magnetic force F is exerted on the projectile. (i) Determine F. F = N [2] (ii) State and explain whether F would be higher or lower in practice as the projectile travels along the rail. [2] (iii) State the direction of F if the direction of the current is reversed. [1] (iv) Explain one way in which F can be increased. [1]

 JJC 2016 8866/JC2 Prelim P2/2016 [Turn Over 9 4 (a) In order to investigate the photoelectric effect, a student set up the apparatus as illustrated in Fig. 4.1. When the potential difference V is varied it is found that the photoelectric current varies as shown in the curve A in Fig. 4.2. Fig. 4.1 Fig. 4.2 (i) Explain why, for curve A, the photoelectric current reaches a maximum value no matter how large V is made. [2] (ii) The intensity of illumination is then increased and the experiment repeated to obtain curve B. Explain why the maximum photoelectric current is increased. [2]

 JJC 2016 8866/JC2 Prelim P2/2016 [Turn Over 10 (b) In a photoelectric emission experiment, light of wavelength 410 nm was shone on a metal surface of work function energy of 2.0 eV so that an area of 2.4 × 105 m2 was illuminated. A photocurrent of 4.8 × 1010 A was observed. Determine (i) the rate of emission of photoelectrons, rate of emission = s 1 [1] (ii) the intensity of the light source, assuming that 1 in 2500 photons succeeds in ejecting an electron from the surface. intensity = W m 2 [3]