9702_s02_qp_2

Candidate Name CandidateNumber

CAMBRIDGE INTERNATIONAL EXAMINATIONSGeneral Certificate of Education Advanced Subsidiary Leveland Advanced LevelPHYSICSPAPER 29702/2MAY/JUNESESSION20021hourCandidates answer on the question paper.No additional materials.TIME1 hourINSTRUCTIONS TO CANDIDATESWrite your name, Centre number and candidate number in the spaces at the top of this page.Answer allquestions.Write your answers in the spaces provided on the question paper.INFORMATION FOR CANDIDATESThe number of marks is given in brackets [] at the end of each question or part question.You may lose marks if you do not show your working or if you do not use appropriate units.FOR EXAMINER’S USEThis question paper consists of 15 printed pages and 1 blank page.SPA(SM/CG) S21690/3©CIE 2002[Turn over2

Data

speed of light in free space,permeability of free space,permittivity of free space,elementary charge,the Planck constant,

unified atomic mass constant,rest mass of electron,rest mass of proton,molar gas constant,the Avogadro constant,the Boltzmann constant,gravitational constant,acceleration of free fall,

c=3.00×108ms–1

␮0=4␲×10–7Hm–1⑀0=8.85×10–12Fm–1

e=1.60×10–19Ch=6.63×10–34Jsu=1.66×10–27kgme=9.11×10–31kgmp=1.67×10–27kgR=8.31 JK–1mol–1NA=6.02×1023mol–1k=1.38×10–23JK–1G=6.67×10–11Nm2kg–2g=9.81 ms–2

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Formulae

uniformly accelerated motion,

s=ut+at2v2=u2+2aswork done on/by a gas,W=p⌬V

gravitational potential,φ=–Gm

r

simple harmonic motion,a=– 󰀂2x

velocity of particle in s.h.m.,

v=v0cos󰀂t

v=±󰀂√(x20–x2)resistors in series,R=R1+R2+. . .resistors in parallel,1/R=1/R1+1/R2+. . .electric potential,V=

Q4␲⑀0r

capacitors in series,1/C=1/C1+1/C2+. . .capacitors in parallel,C=C1+C2+. . .energy of charged capacitor,W=

QV

alternating current/voltage,x=x0sin󰀂t

hydrostatic pressure,p=qghpressure of an ideal gas,p=

NmV

radioactive decay,x=x0exp(–󰀃t)decay constant,

󰀃=0.693

tcritical density of matter in the Universe,q=

3H0208␲G

equation of continuity,Av=constant

Bernoulli equation (simplified),p1+qv12=p2

+qv22Stokes’ law,F=Ar␩vReynolds’ number,Rqe=

␩vr

drag force in turbulent flow,

F=Br2qv2

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4Answer allthe questions in the spaces provided.1Make reasonable estimates of the following quantities.(a)mass of an applemass =...............................................kg[1](b)number of joules of energy in 1 kilowatt-hournumber =...................................................[1](c)wavelength of red light in a vacuumwavelength =...............................................m[1](d)pressure due to a depth of 10m of waterpressure =..............................................Pa[1]2A student uses a micrometer screw gauge to measure the diameter of a wire. He fails tonotice that, with the gauge fully closed, the reading is not zero.(a)State and explain whether the omission introduces a random error or a systematic errorinto the readings of the diameter.................................................................................................................................................................................................................................................................................[2](b)Explain why the readings are precise but not accurate...........................................................................................................................................................................................................................................................................................................................................................................................................................[2]9702/2 M/J02

ForExaminer’sUse53(a)Explain what is meant by the centre of gravity of an object...........................................................................................................................................................................................................................................................................................................................................................................................................................[2](b)A non-uniform plank of wood XY is 2.50m long and weighs 950N. Force-meters (springbalances) A and B are attached to the plank at a distance of 0.40m from each end, asillustrated in Fig. 3.1.ForExaminer’sUseforce-meter Aforce-meter B0.40mX2.50mFig. 3.1When the plank is horizontal, force-meter A records 570N.(i)Calculate the reading on force-meter B.0.40mYreading =................................................N(ii)(iii)On Fig. 3.1, mark a likely position for the centre of gravity of the plank.Determine the distance of the centre of gravity from the end X of the plank.distance =...............................................m[6]9702/2 M/J02

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6A steel ball of mass 73g is held 1.6m above a horizontal steel plate, as illustrated in Fig. 4.1.steel ballmass 73g1.6mhsteelplateFig. 4.1The ball is dropped from rest and it bounces on the plate, reaching a height h.(a)Calculate the speed of the ball as it reaches the plate.speed =..........................................ms–1[2](b)As the ball loses contact with the plate after bouncing, the kinetic energy of the ball is90% of that just before bouncing. Calculate(i)the height hto which the ball bounces,h=...............................................m9702/2 M/J02

ForExaminer’sUse47(ii)the speed of the ball as it leaves the plate after bouncing.ForExaminer’sUsespeed =..........................................ms–1[4](c)Using your answers to (a)and(b), determine the change in momentum of the ballduring the bounce.change =.............................................Ns[3](d)With reference to the law of conservation of momentum, comment on your answerto(c)...........................................................................................................................................................................................................................................................................................................................................................................................................................[3]9702/2 M/J02

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8Some gas is contained in a cylinder by means of a moveable piston, as illustrated in Fig. 5.1.gasmoveablepistoncylinderFig. 5.1State how, for this mass of gas, the following changes may be achieved.(a)increase its gravitational potential energy......................................................................................................................................[1](b)decrease its internal energy................................................................................................................................................................................................................................................................................[1](c)increase its elastic potential energy................................................................................................................................................................................................................................................................................[1]9702/2 M/J02

ForExaminer’sUse596Two horizontal metal plates are situated 1.2cm apart, as illustrated in Fig. 6.1.ForExaminer’sUse1.2cmFig. 6.1The electric field between the plates is found to be 3.0ϫ104NC–1in the downward direction.(a)(i)(ii)On Fig. 6.1, mark with a + the plate which is at the more positive potential.Calculate the potential difference between the plates.potential difference =................................................V[3](b)Determine the acceleration of an electron between the plates, assuming there is avacuum between them.acceleration =..........................................ms–2[3]9702/2 M/J02

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107(a)Figs. 7.1(a) and (b)show plane wavefronts approaching a narrow gap and a wide gaprespectively.(a)(b)Fig. 7.1On Figs. 7.1(a) and (b), draw three successive wavefronts to represent the wave after ithas passed through each of the gaps.[5]9702/2 M/J02

ForExaminer’sUse11(b)Light from a laser is directed normally at a diffraction grating, as illustrated in Fig. 7.2.scaleForExaminer’sUsediffractiongrating162°laser136°Fig. 7.2The diffraction grating is situated at the centre of a circular scale, marked in degrees.The readings on the scale for the second order diffracted beams are 136°and 162°.The wavelength of the laser light is 630nm.Calculate the spacing of the slits of the diffraction grating.spacing =...............................................m[4](c)Suggest one reason why the fringe pattern produced by light passing through adiffraction grating is brighter than that produced from the same source with a double slit.................................................................................................................................................................................................................................................................................[1]9702/2 M/J02

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128A student has available some resistors, each of resistance 100Ω.(a)Draw circuit diagrams, one in each case, to show how a number of these resistors maybe connected to produce a combined resistance ofForExaminer’sUse(i)200Ω,(ii)50Ω,(iii)40Ω.9702/2 M/J02

[4]13(b)The arrangement of resistors shown in Fig. 8.1 is connected to a battery.ForExaminer’sUse25Ω100Ω25ΩFig. 8.1The power dissipation in the 100Ωresistor is 0.81W. Calculate(i)the current in the circuit,current =................................................A(ii)the power dissipation in each of the 25Ωresistors.power =...............................................W[4]9702/2 M/J02

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149The radiation from a radioactive source is detected using the apparatus illustrated inFig. 9.1.detectoraluminium6cmradioactivesourceshieldingFig. 9.1Different thicknesses of aluminium are placed between the source and the detector. Thecount rate is obtained for each thickness. Fig. 9.2 shows the variation with thickness xofaluminium of the count rate.count rate/s–140003000200010000012345x/mm6Fig. 9.29702/2 M/J02

ForExaminer’sUse15(a)Suggest why it is not possible to detect the presence of the emission of α-particles fromthe source.................................................................................................................................................................................................................................................................................[1](b)State the evidence provided on Fig. 9.2 for the emission from the source of(i)β-particles,.........................................................................................................................................................................................................................................................................................................................................................................................................(ii)γ-radiation..........................................................................................................................................................................................................................................................................................................................................................................................................[4]9702/2 M/J02

ForExaminer’sUse16BLANK PAGE

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