2025 CHIJ 4E5N Sci Phy Prelim MS

1 CONVENT OF THE HOLY INFANT JESUS SECONDARY 2025 4 EXPRESS PRELIMINARY EXAM SCIENCE (PHYSICS) 5086 – MARKING SCHEME Paper 1 1 2 3 4 5 6 7 8 9 10 A D D C B D A C D C 11 12 13 14 15 16 17 18 19 20 A A B A C A D A D C Paper 2 Section A 1 (a) It is the rate of change of velocity. [1] both DO NOT accept change of speed. (b) (i) The acceleration increases. [1] (ii) constant/uniform acceleration. [1] (c) acc = ଽ଴଴଴ି଻଴଴଴ ଵହ଴଴ିଵ଴଴଴ = 2, F = 7.4 x 106 x 2 = 1.48 x 107 N [1] [1] Answer in standard form is not required. Allow ecf 2 (a) Force A [1] (b) The cyclist will decelerate. [1] (c) (i) KE of the girl = ½ x 70 x 112 = 4235 All KE has converted to internal energy, hence work done to make the bicycle come to rest = 4230 (3sf) Unit = Joule [1] [1] accept 4235 [1] accept J (ii) Kinetic store to internal store. [1] accept heat energy 3 (a) X: gravitational potential store Y: kinetic store [1] [1] (b) Mass = density x volume = 1000 x (10000) = 1.0 x 107 kg GPE = 1.0 x 107 x 10 x 50 = 5.0 x 109 J [1] [1] answer in standard form is not required. Allow ecf 4 (a) Draw convection current on Fig. 4.1. When the air surrounding the burner is heated up, it expands and becomes less dense and rises. [1] [1] [1]

2 The colder air which is denser will sink to replace the heated air. A convection current is set up. [1] do not need to give if mark is already given for the convection current drawn on Fig. 4.1 (b) Dull black is a good emitter of radiation. It emits heat faster from the chimney to the surrounding. [1] [1] 5 (a) For transverse wave, the displacement of particles is perpendicular to the wave motion whereas the displacement of particles is parallel to the wave motion for longitudinal wave. AND any relevant answers. [1] (b)(i) One wavelength = 1.2 x 104 m Distance between J and K = 1.5 wavelength Distance = 1.5 x 1.2 x 104 = 1.8 x 104 m Distance = 18 km [1] [1] (b)(ii) V = fλ, f = 4800/12000 = 0.4 Hz Period = 1/0.4 = 2.5 s Time taken to make 5 oscillations = 5 x 2.5 = 12.5 s [1] [1] allow ecf 6 (a) A is softer than B since the amplitude of A is smaller than that of B. [1] Answer needs to explain using amplitude. (b) A has lower pitch than C since A has lower frequency than B. [1] answer needs to explain using frequency. 7 (a) 1.47 = ௦௜௡ଷହ೚ ௦௜௡௥ , r = 23o [2] (b) Corn oil and glycerol has the same optical density. OR The speed of light does not change when it passes from corn oil to glycerol. [1] (c) A ray that is bent away from the normal is drawn. [1] 8 (a) 0.08 m [1] (b) Diminished/real/inverted (any two) [2] (c) Camera/eyes [1] (d) A virtual image has been formed as the object distance is less than the focal length of the lens. [1] mark awarded as long as virtual image is mentioned.

3 9 (a)(i) I = 10/20 = 0.50 A [1] award mark if students writes 0.5 A (a)(ii) Total resistance = 15 + ቀ ଵ ହ + ଵ ଵ଴ + ଵ ଵ଴ቁ ିଵ = 17.5 Ω I = 10/17.5 = 0.571 A [1] [1] allow ecf (b) The resistor