Paper 2 Jun 2000 Physics

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

1(a)

speed in increases or or pa parachutist ac accelerates acceleration decreases or increase of speed decreases until until accele accelerat ration ion zero zero or or constan constantt speed/t speed/term ermina inall veloci velocity ty reache reached d

3

(b)

50 m/s and 5 m/s

1

(c)

a = ∆v/t = 4.5-5.0 m/s 2 no more than 3 s. f.

2

2(a)(i)

P=F/A in any form, symbols or words

1

(ii)

F=P.A F = 40 000 F = 100N (not 10kg alone)

3

Any two from: larger area of glass covered by cup/bigger cup /larger area of cup lower pressure inside cup larger atmospheric pressure

2

solid olid gets lar larger/ ger/lo long nger er/e /exp xpan ands ds when hen heat heateed or hot hot or at hig higher  her  temperature

1

atoms ar are fu further ap apart (n (not at atoms ex expand) atoms vibrate or move faster

2

the rim contra tracts or returns to norma rmal or compres resses wheel when cooled or in normal or everyday use or when heating stops

1

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

2

m = E/L E = 400 x 7200 m = 1.28 kg

3

(b)

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

4(a)

(b)

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© UCLES 2002  

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

5(a)

the magnet ha has magnetic fie field lines or or li lines flu flux these lines cut coil / or the flux through the coil changes

2

at le least on one recognisa isable wave (may st start at at an any positi ition in cycle) le) first cycle correctly marked as 0.2 s

2

increase number of of co coils or tu turns / turn magnet fa faster /  use a stronger magnet / less air gap / more soft-iron

2

6(a)(i)

voltmeter across cell or terminals XY correct symbol needed

1

(ii)

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

2

(iii)

the metal resistance increases and thermistor decreases

1

(b)(i)

thermistor reason DI (or DR) large(r) or scale divisions larger  (metal reason DI greater change at first [0-50])

1

(b) (c )

(ii)

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

7(a)(i)

2.9-3.1 cm

1

(ii)

v = fλ seen s een or time for one wave = 1/20 = 0.05s v = 20 x 3.0 v = 3/0.05 60 cm/s

2

(b)(i)

wave of roughly half wavelength

1

(ii)

1.5 cm or half (a)(i)

1

8(a)

electrons re removed fr from or or ru rubbed of off Pe Perspex electrons go onto cloth

2

(b)

C or coulomb

1

(c )

negative on top of A, positive on bottom of A

2

(d)

opposite ite (charges) attrac ract (no (not just -ve attrac racted ted to Perspex) or  force upwards larger than weight

1

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© UCLES 2002  

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

9(a) 9(a)(i (i))

any any appa appara ratu tuss to dete detect ct rad radio ioac acti tivi vity ty (GM (GM tub tubee and and coun counte terr, spar spark k 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

(ii)

or other experimental proof that these particles not present (e.g. no particles where β particles should be deflected)

5

take several readings (counts) (in time or if in space at same distance ) different values obtained (accept other detector ideas)

2

(iii (iii))

handl andlee with with forc forceeps/t ps/to ongs/ ngs/tw tweeezer ezerss or keep dista istan nce from from sour sourcce/  point source away from you or place absorbers in the way (e.g. keep source in lead box or wear lead apron) 1

(b)(i)

134

(ii)

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

1

Po bottom no 84 (iii)

3

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

3

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

6

metal or filament or cathode heated electrons gain enough speed or energy to escape or to be boiled off  or t or thermionic emission described

2

anode is is po positive or or ca cathode is is ne negative or or p. p.d. be between an anode an and cathode anode or positive attracts electron or cathode or negative negative repels electron

2

(c)(i)

5 squares used (e.g. 5 seconds as answer) 0.05s or 50ms

2

(ii)

f=1/T = 1/0.05 = 20 Hz

2

(iii)

twice as many waves on screen or length of one wave halved etc

1

10(a)

(b)(i)

(ii) ii)

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© UCLES 2002  

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

11(a 11(a)( )(i) i)

wate waterr exp expan ands ds on hea heatin ting g or dens densit ity y decr decrea ease sess on on heat heatin ing g hot hot wat water  er  (not heat) rises cold water falls or circulation described 3

(ii)

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 3

(b)(i)

energy = mcT change in temperature = 5 ˚C 3x4200x5 (= 63 000J)

2

time seen as 30 s P = E/t = 63000/30 = 2100W

2

number of hours = 3/60 =0.05 power in kw =2100/1000 Number of kWh = 2.1 x 0.05 = 0.1(05)

3

Any two from: evaporation conduction/convection conduction/convection to surroundings described radiation

2

(ii) (iii) (c )

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