Paper 2 Jun 1999 Physics

Answer guide for O Level Physics (5054/2) – Paper 2 Theory June 1999

1(a) (b) (c) (d)

2(a) (b) (c)(i) (ii)

3(a)

5.2 m/s a = change in speed/ time taken

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e.g. a = (5.2-2)/0.32 = 10 m/s2 2.6 m/s

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K.E. before = ∫ mv2 = 3.1 J K.E. after = 0.78 J K.E. lost = 2.3 J

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correct incident & reflected ray reflected from a point on the surface 1 of the window anywhere between d and w of the word ‘window’ image is beneath the window and vertically below B 1 the same distance below the window as B is above correct position of X between 2nd-4th dashed line from right of arrow ray from B reflected correctly at right side of window

(ii)

Any three from: same speed (in vacuo) travel in a vacuum transverse carry energy or cause warming have wave properties of diffraction, refraction oscillations of electric and magnetic fields v = fλ 0.020 m correct position between 0.1 and 0.01 m

4(a)(i) (ii)

18 Ω 1RT = 1/R1 + 1/R2 leading to 3Ω for the two resistors in parallel

(b)(i)

RT = 9Ω

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(iii)

2Ω

(b)

I=V/R I1 = 1.35/9 = 0.15A

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I2 = I3 = I1 /2 = 0.075A

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Answer guide for O Level Physics (5054/2) – Paper 2 Theory June 1999

5(a)(i) (ii) (b)

6(a)(i) (ii) (b)(i) (ii)

7(a) (b) (c)

8(a) (b)

9(a) (b)(i) (ii) (c)

(d)

(e)

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a charge experiences a force equally spaced parallel lines between plates arrow on all going from the positive to negative plate +ve charge on right side and -ve charge on left side of ball field lines drawn in towards ball

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side AB DOWN and side CD UP Fleming’s left-hand rule explained with magnetic field current and direction current reverses forces are in opposite directions or reverse

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molecules move at random hit the (tyre) wall molecules move faster hit walls harder, more often or more frequently more molecules hit per second or more frequent hits

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F=mxa Resultant force = 800 x 1.4 = 1120 N driving force =1520 N friction and/or air resistance increases so there is less resultant force

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the energy needed to evaporate 1 kg water without change in temperature (0) 1.60 3.43 4.96 6.72 (0) 3800 7600 11400 15200 axes correct with units and points cover at least 5 by 7 large squares points plotted correctly on a sensible scale, not one where each large square is 3,7,9 etc neat sensible thin line drawn gradient method clear using more than half the drawn line value obtained 2250-2350 with no more than 3 significant figures the gradient equals the specific latent heat of vaporisation energy or power is four times greater four times as much water evaporated (in 100s) giving the same result for the specific latent heat

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Answer guide for O Level Physics (5054/2) – Paper 2 Theory June 1999

10(a)(i)

(ii) (b)(i) (ii) (iii)

(c)

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Any three from: nucleus absorbs neutron the nucleus splits neutrons are released particles move off at high speed or with high KE ϒ-particles released two nuclei come together one (larger) particle (nucleus) results from the split nucleus or the products of fission (not decay of uranium) emission of any one or more of α β ϒ-particles from the nucleus Any two from: metal or water absorbs radiation water keeps cans cool waste is kept at distance from humans while it decays any sensible statement of use the length of half-life correct for the use stated a reference to a source of the radiation a reference to the detection of radiation or what happens to radiation a suitable type of radiation suggested

© UCLES 2002

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Answer guide for O Level Physics (5054/2) – Paper 2 Theory June 1999

11(a)(i)

(ii)

(b)(i)

(ii)

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in day air rises above land OR falls over sea at night air rise above sea OR falls over land statement or correct convection current shown on a diagram diagram(s) showing both currents correctly in the daytime and night-time air expands above hot area OR contracts above cold area correct reference to density change of air hot air rises and cold air falls OR a convection current formed no radiation from the Sun during the night land and/or sea loses heat (by radiation or convection) the sea has greater heat capacity OR more (mass) water is heated/ cooled than on land detection apparatus clear for both black and white (eg metal plates +cork, thermometers, foil on back of hand) method of producing radiation (eg Sun, heater, candle, bulb) black and white surfaces equidistant from radiation (accept from diagram) OR in (ii) detector equidistant from black and white surfaces correct observation method of obtaining black and white surfaces of reasonably same temperature method of detecting radiation (e.g. thermopile, thermotransistor, blackened thermometers, not back of hand)

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