Paper 2 Jun 2000 Physics

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

1(a)

(b) (c)

2(a)(i) (ii)

(b)

3(a) (b)(i) (ii)

4(a)

(b)

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speed increases or parachutist accelerates acceleration decreases or increase of speed decreases until acceleration zero or constant speed/terminal velocity reached 50 m/s and 5 m/s

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a = ∆v/t = 4.5-5.0 m/s2 no more than 3 s. f.

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P=F/A in any form, symbols or words F=P.A F = 40 000 F = 100N (not 10kg alone) Any two from: larger area of glass covered by cup/bigger cup /larger area of cup lower pressure inside cup larger atmospheric pressure

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solid gets larger/longer/expands when heated or hot or at higher temperature atoms are further apart (not atoms expand) atoms vibrate or move faster the rim contracts or returns to normal or compresses wheel when cooled or in normal or everyday use or when heating stops Any two from: faster moving or more energetic molecules escape leaving behind slower or less energetic molecules or mean molecular energy decreases temperature related to mean molecular energy energy is required to break bonds or latent heat is needed m = E/L E = 400 x 7200 m = 1.28 kg

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

5(a) (b) (c)

6(a)(i) (ii)

(iii) (b)(i)

the magnet has magnetic field lines or lines flux these lines cut coil / or the flux through the coil changes at least one recognisable wave (may start at any position in cycle) first cycle correctly marked as 0.2 s increase number of coils or turns / turn magnet faster / use a stronger magnet / less air gap / more soft-iron

voltmeter across cell or terminals XY correct symbol needed I,V measured or known or ammeter gives current and voltmeter gives voltage R=V/I stated in a clear manner or gradient of (V,I) graph found the metal resistance increases and thermistor decreases thermistor reason DI (or DR) large(r) or scale divisions larger (metal reason DI greater change at first [0-50])

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(ii)

metal reason DI (for 0 to 50oC) is same/constant (from 50 to 100oC) 1

7(a)(i) (ii)

2.9-3.1 cm v = fλseen or time for one wave = 1/20 = 0.05s v = 20 x 3.0 v = 3/0.05 60 cm/s wave of roughly half wavelength 1.5 cm or half (a)(i)

(b)(i) (ii)

8(a) (b) (c) (d)

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electrons removed from or rubbed off Perspex electrons go onto cloth C or coulomb negative on top of A, positive on bottom of A opposite (charges) attract (not just -ve attracted to Perspex) or force upwards larger than weight

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

9(a)(i)

(ii)

(iii)

(b)(i) (ii)

(iii)

10(a)

(b)(i)

(ii)

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

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any apparatus to detect radioactivity (GM tube and counter, spark counter etc) any reading taken (e.g. count, count rate mentioned) paper or a few cm air used as absorber or electric or magnetic field used shows decrease (to background) or correct field deflection for α nothing or background through paper or few cm air so no β or only α or other experimental proof that these particles not present (e.g. no particles where β particles should be deflected) take several readings (counts) (in time or if in space at same distance) different values obtained (accept other detector ideas) handle with forceps/tongs/tweezers or keep distance from source/ point source away from you or place absorbers in the way (e.g. keep source in lead box or wear lead apron) 134

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α−particle top no 4 α−particle bottom no 2 Po bottom no 84

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formula E = mc2 1.14.10-29 x (3x108)2 1.0(26) x 10-12 J

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basic complete outline shape vacuum labelled fluorescent screen labelled X and Y plates labelled filament and/or cathode correctly labelled anode as plate with hole or cylinder labelled metal or filament or cathode heated electrons gain enough speed or energy to escape or to be boiled off or thermionic emission described anode is positive or cathode is negative or p.d. between anode and cathode anode or positive attracts electron or cathode or negative repels electron 5 squares used (e.g. 5 seconds as answer) 0.05s or 50ms f=1/T = 1/0.05 = 20 Hz twice as many waves on screen or length of one wave halved etc

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

11(a)(i)

(ii)

(b)(i)

(ii) (iii) (c)

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water expands on heating or density decreases on heating hot water (not heat) rises cold water falls or circulation described source of local heat clear (accept arrow on diagram) method of detecting circulation, e.g. smoke, dye, aluminium or soot particles convection current shown on diagram and complete and consistent with position of source energy = mcT change in temperature = 5 ˚C 3x4200x5 (= 63 000J) time seen as 30 s P = E/t = 63000/30 = 2100W number of hours = 3/60 =0.05 power in kw =2100/1000 Number of kWh = 2.1 x 0.05 = 0.1(05) Any two from: evaporation conduction/convection to surroundings described radiation

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