Paper 2 Nov 2000 Physics

Answer guide for O Level Physics (5054/2) – Paper 2 Theory November 2000

1(a)(i) (ii) (b)(i) (ii)

2(a)

(b)

C lowest K.E. at C or K.E. decreases as ball rises P.E. rises as ball rises or highest P.E. at C 2.0 or 2N K.E. = ∫ mv2 2.5 = 0.2 v2 / 2 or equivalent substitution 5 m/s

diagram with correct triangle or parallelogram ruled scale diagram or trig equation 33-36N or 34.6N or 35N W=Fxd 3.2 J (or Nm)

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3(a)

molecules move around molecules move at random or molecules have high speed /K.E or molecules move from high to low concentration or molecules free to move 2

4 (a)

Two correct rays from (provided none wrong): ray from A or B parallel to axis refracted through ray from A or B passes straight through optical centre ray from A or B through F1 refracted parallel to principal axis ray parallel to axis through F1 from A or B

(b)(i) (ii)

(c)

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splitting of light into colours/frequencies/wavelengths/spectrum at side A, a single ray/line continues straight at side B, refraction away from normal for all rays shown at this face at least 2 rays emerging from side B, labelled colours/spectrum 2 camera / (slide) projector / (photographic) enlarger / eye etc 1

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Answer guide for O Level Physics (5054/2) – Paper 2 Theory November 2000

5(a) (b) (c) (d)

heat/energy/work to change liquid to gas / water to steam / evaporate/ boil water, for 1g /unit mass/1kg steam condenses or steam changes to water energy = mc(∆T = 500 x 4.2 x 80 1.68 x 10 5 J

(ii) (b)

7(a) (b)

(c)

8(a) (b)

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H = mL = (c)/2250 final mass = 74.6(6) + 500 = 575g

6(a)(i)

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arrows in rough circle clockwise (from above) close to wire/current or in middle of board mark one end or direction of arrow move compass on to marked end join marks or repeat process round wire

2p+2n /He nucleus / nucleon(mass) number 4 β−particles are less ionising (so lower current) or β−particles more penetrating (e.g. escape detector, pass through plates) 95 protons (accept proton number 95) 146 neutrons 95 electrons outside nucleus or in shells

R=V/I = 3.8/0.25 = 15-15.4 Ω ( quoted to 2/3 sig. figs) slope decreases or V/I more by calculation as p.d. or current rises temperature rises

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Answer guide for O Level Physics (5054/2) – Paper 2 Theory November 2000

9(a)(i) (ii) (iii) (b)(i) (ii)

(iii)

10(a)

(b)

(c)(i)

(ii)

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energy/charge or power/current I = P/V = 36/6 6A current/power/brightness/temperature of lamp too large lamp blows / breaks / melts / burns out / reduces life of lamp 4V 6A or same as (a)(ii) 1. diagram with labelled core two separate coils with clear ends turns in ratio 10:6 primary to secondary made clear 2. reference to magnetic field/flux in core/coils varying field or flux induction of emf or current in output coil or field /flux cuts or is linked with output coil B since more power/energy/heat wasted in resistor R or not sure because power loss/efficiency transformer unknown or A works with ac and dc

Any three of these four points: compressions and rarefactions oscillation/vibration of (air) molecules back and forth vibration along the direction of travel / parallel direction wave longitudinal diagram showing slinky spring / air layers (audible) frequency (of whistle) between 20 and 20000Hz (unit needed) mention of microphone diagram with microphone connected to CRO or basic CRO showing X/Y plates & anode adjust timebase /y-gain / shift(s) for number/position /height of waves measure/use length of one wave on screen (accept wavelength) note down or use timebase setting / no. of sec per division multiply length by timebase to give time for 1 oscillation 1. amplitude decreases 2. same distance between waves/ same period /same number of cycles on screen two waves of different frequency drawn clear which has the higher frequency labelled

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Answer guide for O Level Physics (5054/2) – Paper 2 Theory November 2000

11(a)

(b) (i)

(iii) (c)(i) (ii) (iii)

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outline of tank containing water labelled bar/dipper or suitable plane wave producer, e.g. square or roller from side, not circle or cork suspended and with motor/vibrator on dipper or moved by hand strobe (e.g. hand-held) or light and screen waves may speed up or slow down in this section parallel waves on right of boundary at least 1 wave joining wave on left at boundary and no mistakes change water depth how this is done e.g. place glass obstacle below surface waves change speed (not just a change in density) s =d/t = 4.5/0.75 (or 1.5/0.25 or 3.0/0.50) (or use v=fλ with later values) 6 cm/s 1.5 cm (or use λv/f ) v = f λ or t = 1/f f = 6/1.5 or 6 = 1.5f or t = 0.25 s 4 Hz

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