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1. Force per unit positive charge B1[1]
2. (i) Suitable recognisable pattern around (not just between) the charges B1Quality mark: symmetry spacing lines joined to charges B1!onsistent arrows toward B on some lines B1
(iii) 6he separation between the ions because this has an e##ect on the
breaking #orce/ (5llow the si7e o# ionic 8charges9) B1[7]
3. (a) (i) ! p % + ' % 0 ;F 51
(ii) 1/! % 1&+ < !1
!s % '&= %1/== ;F 51 (b) (i) 0/* 4 51
(ii) Q % ! p4 !1
% 0 - 0 % =0 ;! 51
(c) $ % > !s4 + !1% +' - 1* 0 51
(d) (i) 6he capacitors discharge through the voltmeter/ B1
(ii) V %V *e t &CR
1&' %e t &(0-1+) !1ln ' %t & 2+ !1t % 2+ ln ' ? 1** s 51
[12]
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4. 5ny seven #rom:@ A particle scatteringsuitable diagram with source #oil moveable detector + or more trajectories shownvacuummost particles have little i# any de#lectionlarge de#lection o# very #ewre#erence to !oulomb9s law &elastic scatteringalphas repelled by nucleus (positive charges)monoenergetic
C electron scatteringDigh energy diagram with source sample moveable detector & #ilm4acuum$lectron accelerator or other detailEost have 7ero de#lection!haracteristic angular distribution with minimumEinimum not 7ero
e Broglie wavelengthGavelength comparable to nuclear si7e hence high energy B1 - 2
!learly shows how evidence #or the si7e o# the nucleus #ollows #romwhat is described/ (1)
[8]
5. (a) De nucleus a #ew cm & = to 1* cm5bout 1 m & */= to + m & several m 1 to 1* mm 5l & 1 mm Hb
(high energy) eAm radiation 1 to 1* cm o# Hb & several m o# concreteonly + correct 1 mark only ' correct + marks B= (b) Source absorbers placed in #ront o# detector on diagram B1
$Iplanation o# how results identi#y the source(+ marks possible) B+5llowance #or background (maI +)(allow #or distance eIpt to a maI +)
[6]
6. (a) (i) #luI % B - 5 (normal to B) with symbols eIplained B1
(ii) linkage % 3 - #luI B1
5 % x+ so linkage % 3B x+ B1
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(b) (i) Statement o# Faraday9s law or indicatione/g/ 4 % d(3B x+) & dt #rom (a)(ii)4 % 3B x+d x&dt or 4 % 3B xv & argue area swept out per second as xv B14 % 1+J* - */*=+ - */*+ - */1 B1
% */*K or K* m4 B15* (ii) e,ual positive and negative regions B1
e,ual positive and negative values o# 8maIima9 labelled on yAaIis B1value changes within correct time 7ones t % */+ to */' */0 to */K s B18s,uare pulse9 shape B1
sinusoidal graphs score zero marks[10]
7. "niverse is isotropic &same in all directions B1
Domogeneous & evenly distributed B1[2]
8. 5ny #our #rom:"ni#orm intensity in all directions & everywhereStructure in background intensity & ripplesHroduced when matter and radiation decoupled
riginally gamma radiation(gamma) redAshi#ted to microwave & originally higher energy$vidence that universe began with big bang6emperature corresponds to +/2 L & =L & that predicted by big bang model B1 - 'Mink between evidence and eIplanation/ (1)
[5]
9. 5ny two #rom: 3o eIperimental evidence & no physical evidenceState o# matter unknown & laws o# physics unknown$nergies unreproducible & re#/ to very high temperature B1 - +
[2]
10. pen: "niverse eIpands #or all timeFlat: eIpands to a limit (but never reaches it) B1!losed: "niverse contracts & collapses back B1Ce#erence to role o# gravity & critical density B1Earks #or (a) can be gained on a labelled diagram B1
[4]
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11. Do+ % (1 - 1* +0 - K - - 0/02 - 1* 11) & = !1
Do % +/=0 - 1* 1K s 1 51[2]
12. (a) ensity (o# medium) B1Speed o# ultrasound (in medium) or any #actors that a##ect the speed o# ultrasound in the medium e/g/ Noung modulus B1
15. 5ny six #rom:method does not use ionising radiationhence no radiation ha7ard to patient or sta## gives better so#t tissue contrast than !6 scansgenerates data #rom a = volume simultaneouslyin#ormation can be displayed on a screen as a section in any directionthere are no moving mechanisms involved in EC6here is no sensation a#ter e##ects at the #ield strengths used #or routine diagnosisStrong magnetic #ield could draw steel objects into the magnetEetallic objects may become heated!ardiac pacemakers may be a##ected by the magnetic #ields!6 scanners better #or viewing bony structures B1 - 0
[6]
16. (a) Cb .'!s JJ"1'= 1 #or each error B+
(b) 4alues #rom graph: " 2/' Ee4allow 7.3 to 7.
Cb K/0 Ee4allow !." to !.# !1!s K/' Ee46otal binding energies: " +=J - 2/' (12=.)Cb .' - K/0 (K*K) B+!s 1'+ - K/' (11.=)6otal energy released % K*K 11.= 12=. 51% +0+ Ee4allow K/0 K/' 2/' % ./' Ee4 #or 1 mark only
[6]
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17. 5ny siI #rom: (two advantages and two disadvantages needed) problems with the reaction getting out o# controlmaintaining the reaction so that it proceeds continuouslydoes not produce acid rain or waste gases that could cause pollutionrisks #rom radiation: emissions due to an accident (1)Remissions #rom radioactive wastes (1)long hal# li#e o# some o# the waste products (1)other eIamples are likely to be added but should be related to Scienti#icreasons rather than political/ B1 - 0
[6]
18. (a) (i) > mv+ % 2/0 - 1* 1= to give v % (+ - 2/0 - 1* 1= &0/0 - 1* +2 (1)evidence o# calculation v % +/= - 1*1' or % 1/J+ - 1*2 (m s 1) (1) +
(ii) (electrostatic) repulsion between charged particles (1)
slows alpha and accelerates nucleus&5G (1)momentum o# system is conserved(as no eIternal #orces) (1)sum o# momenta o# alpha and nucleus must always e,ual initialmomentum o# alpha&be a constant (1)so speed o# nucleus can be calculated as momentum % mv (1) =max 3
+* (s) + gi$e (%) mark &orchange in momentum % impulseor Tmv % F(T)t
(b) (i) !oulomb #orce @ distance + or F1&F+ % r ++&r 1
+ or Fr + % constant (1)giving F % '/* 3 at 1* - 1* 1'R % 1/K 3 at 1J - 1* 1' m (+) =
(ii) plot and draw correct curveec& plausible $alues in b(i) (1) 1
[13]
19. (a) (i) v % + r# % + - */*1J - J*R % '/2 (m s 1) +
(ii) a % v+&r % '/2+&*/*1JR % 1/J - 1*= (m s +) ec&(a)(i) +
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(iii) the belt tension is insu##icient to provide the centripetal #orceR (1)so the belt does not 8grip9 the pulley&does not hold the belt againstthe pulley&there is insu##icient #riction to pull&push&move the belt/ (1) +alternati$e argument the belt does not 8grip9 the pulley&there isinsu##icient #riction to pull&push&move the beltR because o# itsinertia&insu##icient to provide #orce #or acceleration o# (belt)Adrum
(b) resonance occursR when the natural #re,uency o# vibration o# the (1)
panel % rotational #re,uency o# the motor (1) + (c) (i) 1 J 1J +J (ms)
2 * 1* +* =* (ms) 1 (ii) Stating&using U % dV&dt (1)
gradient % */02 W */*J (Gb turns ms 1)R em# % gradient - 1*= (4) (+) =[12]
(ii) % 4&C % J***&1/+ - 1*1J or % '/10 - 1* 1+ (5) (1) 1
(iii) t % Qo& R % 0 - 1* K & '/10 - 1* 1+ % 1/'' - 1*' (s) +
(iv) Q % Qoe 1R Q % */=2Qo so Q lost % */0=Qo +
(c) (i) capacitors in parallel come to same voltage (1)
so Q stored @ ! o# capacitor (1)capacitors in ratio 1*= so only 1* = Q
o le#t on #ootball (1) =
(ii) 4 % Q&! % 0/* - 1* K &1/+ - 1* K or 0/* - 1* 11 &1/+ - 1* 11 or only 1* =
Q le#t so 1* = 4 le#tR % J/* (4) +[14]
21. (a) (i) e,ually spaced hori7ontal parallel lines #rom plate to plate (1)arrows towards cathode (1) +
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(ii) > mv+ % ,4R v % (+e4&m) % (+ - 1/0 - 1* 1. - 2***&./1 - 1* =1) so (1)v % '/.0 - 1*2 (m s 1) (1) +
(b) (i) arrow perpendicular to path towards centre o# arc (1) 1(ii) out o# paper&upwardsRusing Fleming9s MD rule (#or conventionalcurrent) (+) +
(iii) mv+&rR % B,vR r % mv&B, % 1.=
2=1
1*0/11**/=
1*.0/'1*1/.−−
−
×××
×××R% ./' - 1* +
(m) ' (c) change magnitude o# current in coils to change #ieldR (1)
change #ield to change de#lectionR (1)reverse #ield¤t to change de#lection #rom up to down (1)max ' +[13]
22. (a) (i) +1+R X +(ii) +*KR @ +
(b) range&penetration&absorption eIperiment:
@ place detector very close& +cm #rom sourceR measure count rate (1)use paper screen or move back to 1* cm or moreR contrast to (1) background count level& other emissions #rom same source (1)X place detector eg 1* cm #rom sourceR measure count rate add (1)thin sheets o# 5l until count drops to very low or almost constant value (1)aliter de#lection eIperiment:needs vacuum #or @ eIperimentR (1)source #or radiation passes through region o# $A or BA #ieldR (1)de#lection o# particles detected by detector to distinguish emissionsR (1)detection method (1)max marks '
(iii) !urve passing through (* =+) (0* 10) (1+* K)ec&s &rom (i) (ii) (1) 1
[13]
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23. o not score the same marking point twice* some marking pointsappear more than once in a di&&erent context
&ission is splitting o& nuclei:neutron is absorbed by the nucleusR (1)an (unstable) nucleus splits into two (major) #ragmentsR (1)and several&two&three neutrons (1)charges on&!oulomb repulsion pushes #ragments apartR (1)loss o# mass&increased binding energy accounts #or k/e o# #ragments&release o# energy (1)
&usion is &using o& nuclei+two light nuclei (are moving rapidly enough to overcome the!oulomb repulsion to 8touch9 and) #useR statement in brackets
gets second mark (1)has to be very hot #or nuclei to have enough kinetic energy& only (1)happens naturally inside Sun&staraccept DAbomb (1)loss o# mass&increased binding energy accounts #or release o# energy
similarity : release o# energy&total (rest) mass decrease&9increase9 in (1) binding energy &conservation o# charge&massAenergy etcdi&&erence: &cold hot&heavy light nuclei&large (+** Ee4) small (=* Ee4)energy release per reaction (1)conditions : #ission rate can be varied&controlled by absorbing and or slowing released neutrons in reactor where chain reaction isoccurring&5G (+)max ' marks#usion needs a very hot and su##iciently dense and plenti#ul plasma#or random #usion collisions to occur eg inside Sun&star&5G (+)max ' marks 2Quality o# Gritten !ommunication +
[9]
24. ,ppreciation that key is the di##erence in numbers o# atoms&nucleior e,ual number o# nucleons involvedi& nothing else is achie$ed (1)
-ull argument :+=J g o# uranium and ' g o# hydrogen&helium contain 1 mole o# (1)atoms (1)there are '/+0 moles o# uranium and +J* moles o# helium (1)so at least JK times as many energy releases in #usion (1)
ratio o# energies is only 2 #old in #avour o# uraniumthere#ore more energy release #rom 1 kg o# hydrogenany similar alternati$e argument along same lines scores marks (1)eg For " each nucleon 8provides9 */KJ Ee4 (1)For D each nucleon 8provides9 2 Ee4 (1)(5pproIimately) same number o# nucleons per kg o# " or D (1)so K/+ times as much energy #rom D 'Quality o# Gritten !ommunication +
25. (a) Sketch to include: 4ariable #re,uency 5/! source to primary core coilsR (1)resistor connected to secondaryR (1)appropriate meters in primary and secondary circuitsR (1)Quantities kept constant: 4oltage o# sourceR (1)Hrimary current & powerR (1)Cesistance o# secondary circuit resistorR (1) 3umber o# turns in both coilsR (1)Hrocedure: "se several #re,uencies over a wide range & the range availableR (1)5t each #re,uency read metersR (1)6able headings to show: meter readingsR (1) primary power secondary power e##iciency/ (1)Yraph o# e##iciency against drawnR (1)
etails o# calculations o# power (may use meter readingsand value o# resistor)R (1)$Ipression #or e##iciency & Z e##iciency/ (1) maI 1*
(b) $nergy & heat is lost in core due to hysteresisR (1)
$nergy & heat loss in 1 cycle is proportional to area o# hysteresis loopR (1)Fre,uency increase reduces e##iciency because energy loss(per second) % #re,uency - area enclosed by hysteresis loop/ (1)$nergy loss takes place due to heat generated in core by induced &eddy currentsR (1)
nduced voltage in core increases with #re,uency & is proportionalto #re,uencyR (1)(so) induced current in core increases with #re,uency & is proportionalto #re,uency/ (1) maI '
[14]
26. acts only on nearest neighbour & when nuclei are 1 diameter apartR (1)eitherso #orce holding nucleons& neutrons together independent o# si7e o# nucleus (1)orre#erence to b so distance apart (o# nucleons) must be constantRso density o# nucleus is independent o# si7eR (1) =
[3]
27. (a) +=..+" [ +=.
.= 3p * 1X &* 1e $ (1)
allow+=K.+" 1
*n on MDS+=.
.= 3p [ +=..' Hu *
1X &* 1e $ (1) +
allow neutrino instead o# antineutrinoomits neutrino altogether A gets 1&+
(b) straight line starts #rom 7ero and reaches 1/*K - 1*1=att % 0/* - 1*J s or e,uivalent (1) 1
29. (much) greater energy per unit mass o# #uel (1^)detail: greater change o# binding energy & nucleon #or #usion than #ission (1)no & little radioactive waste (1^)detail: byAproduct is (stable) helium (1)materials in _$6 structure will not become radioactive over long period (1)tritium has short hal#Ali#e (and is used anyway) (1)#uel & reactants (virtually) limitless (1^)detail: deuterium available #rom water (1)deuterium easily separated #rom normal hydrogen (1)lithium is a common material (1) but not tritium is widely availableno chance o# runaway & meltdown (1^)
detail: only minute ,uantities o# reactants (in vessel) (1)reaction ceases immediately (temperature #alls) (1)any two reasons (^) ` 1mark corresponding detail ` 1 mark % + +accept other valid answers
[4]
30. (a) +=0.+" [ 1**
'* r 1=1J+6e J1*n (1) 1
(b) (i) nucleon number: no change
proton number: increases by (1) 1(ii) nucleon number: 1**
(c) (i) sine or cosine curveR amplitude K/* - 1* 1+ mR period % 1/J - 1* 1' s =(ii) resonance situationR driving #re,uency o# radiation % natural (1)
#re,uency o# oscillation o# molecule&5G (1) +[15]
33. 5: the number o# (undecayed) nuclei which decay per second&rate o# decay o# nuclei 1O: the probability o# a given nucleus decaying in the neIt second or in unittime&the (decay) constant relates the activity to the number o# undecayed nuclei 1 3: the number o# undecayed nuclei&nuclei o# the original nuclide (remaining) 1
(iv) O % */0.&6 % */0.&'/J - 1*. - =/+ - 1*2 % '/K - 1* 1K (s 1) 15 % O3 % '/. - 1* 1K - =/J - 1*+J % 1/2 - 1*KR s 1 or B, +
[6]
35. #orce per unit (positive) charge 1#orce per unit mass 1#orce per unit length o# conductor carrying unit currentR 1 perpendicular to #ield and current 1
examples o& similarities :all eIplain action at a distance 1all #orces per unit something / 1#ield lines never crossR density o# lines indicates relative strength o# #ield +$ and g have the same laws&geometry e/g/ #or point and&or plane distributionsR 1#or $ and g #orce in direction o# #ieldR #ield lines perpendicular to sur#ace +
examples o& di&&erences+#orces caused by di##erent entitiesR and act di##erently i/e/ $ and gdi##erent to BR 1#orce caused by stationary versus moving chargeR +direction o# #orce #or B given by F/M/D/rule etc/ +g is only attractive $ (and B) can cause attractive and repulsive #orces 1#ield lines #or B #ield closed loops others start and #inish on m Q 1magnitudes o# #orces very di##erent #or unit R detail/ +max 7 marks
,uality o# written communication +[9]
36. magnetic #luI % B5 1meanings o# B and 5 i/e/ #luI density or #ield strength and area⊥ to it 1magnetic #luI linkage re#ers to the #luI linking&passing through a coilR 1and e,uals 3 - #luI where 3 is the number o# turns (o# the coil) 1Faraday9s law: induced e/m/#/&voltage is proportional to rate o# change o# #luIlinkage through it &correct mathematical #ormulation&5G 1Men79s law: the direction o# the induced e/m/#/&voltage is such as tooppose the motion&change that produced it 1relationship o# Men79s law to conservation o# energy or other valideIplanation&discussion&description +max " marks
rotated around patient & the signal & PAray passes through thesame section o# the body #rom di##erent directions/
producing a (thin) slice & crossAsection/dea o# absorption & less gets through & more is absorbed
by dense material & bone & material o# high & Digh related tomaterials such as bone & Mow to materials such as so#t tissueattenuation is by the photoAelectric e##ectthe possibility o# using a contrast medium/better than a simple PAray at di##erentiating other organs/patient is moved a small distance and the process is repeated &
process continues in a spiral/a computer (analyses the data) & identi#ies the position o# organ&bone
and #orms a =A image/ 2 (b) Hatients are eIposed to ionising radiation/ (1)
5 p/d/ & voltage must be applied causing the (pie7oelectric) crystal to change shape/
5 named crystal (eg ,uart7 lead 7irconate titanate \H 6] lithium sulphate barium titanate)
5n alternating p/d/ causes the crystal to oscillate & vibrate (accept resonate)/
# the #re,uency applied matches the natural #re,uency o# the crystalresonance occurs/6he crystal is damped & stops vibrating when the applied voltage stops
due to the backing material & epoIy resin which also absorbs backwardAtravelling sound waves (which
might give spurious re#lections)/ J[5]
39. (i) J/' cm & */1 cm read #rom the graph (1)% J/' - +* fs cm 1 - 1/J - 1*= m s 1 (1)% */10+ m (1)*/10+ & + % */*K1 m or K/1 cm (1) '
(ii) Digh re#lection at the airAskin boundary & Mittle ultrasound enters
the body & 5 very large peak right at the start (1) due to large di##erence in acoustic impedance &
allow 8 due to large di##erence in density9/ (1)4ery low peaks & no (subse,uent) peaks (not just 8nothing9) (1) =
40. (i) (neutrons) having energies comparable with thermal energies &slow moving & low kinetic energy & energy in range 0 A 1** e4 &energy similar to (energy o# ) atoms o# surroundings R 1
(ii) either thermal neutrons will be captured & absorbed (by "A+=J nuclei)
or higher energy neutrons do not get absorbedR 1 [2]
41. (i) = points plottedR any point incorrect loses this mark 1(ii) curve through = points and heads down towards 7eroR (1)
45. (a) number o#decayed "A+=K nuclei % > - number o#undecayed "A+=K nucleiR (1)so 1&= o# "A+=K has decayed and +&= o# "A+=K has not decayedR (1) +(so ratio % +&=)
(b) either O % */0.= &2 > % */0.= & ('/'2 - 1*. ) (% 1/JJ - 1* 1* y 1) subs/ (1) % * e Ot so : * % e Ot and ln ( : *) % Ot ln (*/002) % 1/JJ - 1* 1* t alg/ & arith/ (1)so t % +/01 - 1*. y ans/ (1) =
or : * % (>) x
so */002 % (>) x
and ln (*/002) % x ln(*/J)and x % */JK' thent % x 2 > % */JK' - '/'2 - 1*. % +/01 - 1*. y
48. (a) one (or more) electrons removed (or added) to an atom 1(b) $ % h# % hc&O together with knowledge o# symbol meaning (1)
%.
K='
1*+=K
1***/=1*0=/0−
−
×
××× (1)
% K/=0 - 1* 1. (_) (1) = (c) #re,uency o# "4 is greater than #re,uency o# light
C alternative statement in terms o# wavelength/so photon energy o# visible light is less than photon energy o# "4 (1)HM"S one o# the idea o# conservation o# energyit is not possible #or a low energy photon to give a high energy photonthis is a one to one process (1) +
(d) $ % 4&d and power o# 1* correct #or d (1)
% =*&*/***+* % 1J* *** (1)4 m 1 (1) =
[9]
49. (a) appropriate shapeR lines perpendicular to and touching plate and sphereR (+)arrows towards negative sphere (1) =
(b) (i) By moments e/g F cos +* % G sin +* & by triangle o# #orces &
(d) #ield line sketchminimum o& " lines symmetrical about line >oining centres with arrows R (1)Fig 1 sketch matches CDS o# Fig +&plate analogous to mirror&5Grelating to symmetry (1) +
(ii) n % Q&e % 1/1 - 1* 1*&1/0 - 1* 1.R % 0/. - 1*K allow sig. &ig. $ariations +
(iii) 5 % O3R 3 % 0/. - 1*K&1/K - 1* 1*R % =/K - 1*1K using 7.? gi$es 3.@ = (iv) 1 y is less than 1Z o# 1+* y so eIpect to be within 1Z&
using e Ot gives eIactly 1Z #all& problem o# random emissionor other relevant statement 1
[11]
51. (a) (i) F is towards 8open9 end o# tubeR using Fleming9s M/D/ rule +(ii) F % B w 1(iii) F % */1J - K** - */**+JR % =/* (3) +
(b) (i) 5 voltage is induced across moving metal as it cuts lines o# #luI&5GR (1)
voltage is proportional to #luI change per second&5GR (1)the #luI change per second is Bwv & is proportional to the area o# metal moving through the #ield per second & is proportional to v (1)or Faraday9s law #ully statedR with reasonable attempt toR (+)relate #luI linkage per second proportionally to speed (1) =
(ii) #luI (linkage) doublesR so using Faraday9s law 4 doubles&5G +
52. nature and #eatures:@Aparticle is +p +n& mass ' u (1)charge o# +e (1)very short range&heavily ioni7ing&absorbed by paper (1)spontaneousR and random nature o# radioactive decay (+)energetically more #avourable to eject #our particles together than a singleone&other comment about energy minimisation&mainly occurs #rom higher 5 nuclei&5G (1)small mass decrease&loss provides kinetic energy o# @Aparticle (1) particle energy o# a #ew Ee4R particular decay is monoenergetic (+)@Aparticle scattering:suitable diagramand/or description to illustrate eIperimentup to ' marks (+)most particles have little i# any de#lection (1)large de#lection o# very #ew shows nucleus is smallR and very massive (+)(!oulomb9s law enables closest approach to) estimate nuclear si7e(in case o# @Aparticle back scattering with conservation o# energy argument) maI 2Quality o# Gritten !ommunication +
[9]
53. description:(') hydrogen or light nuclei&protons are #used together to #orm ahelium&heavier&larger nucleusR (1)two positrons must also be releasedR to conserve chargeR (+)the process is more complicated than the summary e,uation suggests&5GRmass reduction provides energy release& m % $&c+ (1)the process re,uires very high temperatures (to bring the protons together)R (1)normally achieved inside a starR only by man in a bomb so #arR (1)comparison: (+)$nergy release in #usion is much greater than in radioactive decayR because mass reduction&change in #usion is much greater than in radioactive (1)decay&5GR (1)as the helium nucleus is so strongly boundR (1)also energy release #rom annihilation o# positronsR (1) maI JQuality o# Gritten !ommunication +
55. Dydrogen atoms&particles (1)!ollapse under gravity& decrease o# gpe (1)
ncrease in kinetic energy& temperature (1)Fusion o# protons (1)$nergy released& re#/ to $ % mc+ (1)
[5]
56. v @ r & v % Do - r (1)labels (including one re#erence to $arth&Sun&YalaIy) (1) +
[2]
57. in#inite "niverse (1)all lines o# sight end on star (1)so night sky should be bright& not dark (1)either eIpanding "niverse&light undergoes red shi#t (1)more distant galaIies have greater red shi#t (1)or age o# "niverse is #inite (1)light #rom distant stars not yet reached $arth (1)
[5]
58. (i) accept description of plan view or side view.
side: central bulge (1)galactic disc each side (1)
(ii) correct position o# Sun (accept +K***ly #rom centre) (1) 1
[3]
59. (i) hydrogen & helium gas (1)#ormed a#ter big bang & remnants o# supernovas (1)
(ii) critical density is condition #or #lat "niverse/ (1)dark matter increases density o# "niverse/ (1)density greater than critical density/ (1)"niverse will contract & big crunch/ (1)
60. For ation of i a!e to a ax 3 e/g/PArays are detected by a #ilm & scintillation counter etc/ (1)Digh 8 9 means high attenuation & low transmission\5llow atomic mass & nucleon number] (1)
shadow on the #ilm & re#erence to eIposure a#ter attenuation (1)Ce#erence to photoelectric e##ect & energy range around 1 1**ke4 &absorption = (1)"xplanation of the #se of a contrast edi# to a ax.4 e.!.
PArays do not di##erentiate & show up so#t tissues well (1) as similar absorption & 8 9 is similar & 8 9 is low #or these tissues/ (1)
!ontrast medium has high 8 9 & absorbs PArays strongly/(1)t is usually taken orally & as an enema & can be injected/(1)
"xa ple of t$pe of str#ct#re that can %e i a!ed to a ax.1 e.!.
digestive tract & throat & stomach/(1) to a maI/ K[8]
66. all #ree hadrons (thought to be) (somewhat) unstableR (1) protons and neutrons are (both) hadronsR (1) (1) protons and neutrons inside a nucleus are stableR (1)#ree neutrons have hal# li#e o# 1* A 1J minutesR (1)#ree protons are stable & have hal# li#e o# about 1*=+ yearR (1) any Jallow e,uivalent marks #or other hadrons and & or other relevant points
[5]
67. (i) weak (#orce & interaction)R (1) 1
(ii) =1D [ =
+De * 1e $ R (1) 1
(iii) d [ u e $ R (+)
d [ u gets 1&+ud [ u e & X $ is not in simplest #orm so gets >d
baryon reaction1*n [ 1
1 p *
1e $ gets > +
[4]
68. #ission is when splitting (into two parts releasing energy) takes place and#usion is when joining together takes place (1)nuclei as the active particles (1) +
(c) e/g/ i# run at .+ L there is a danger that superconductivity will cease as aresult o# a slight temperature rise (1)a 1J L di##erence provides a sa#ety region (1)22 L is the boiling point o# li,uid nitrogen (1)other sensible suggestion (1) +
" +=J ion with slightly smaller radius (1) paths curving upwards (1) =
[16]
71. (a) (mv %) =**R kg m s 1 or 3 s (+) +
(b) (i) (6he speed o# the bar increases so) it is accelerated #orwards&5GR (1)this re,uires a resultant (#orward) #orce&F % ma idea (1) + (ii) 5rrow in direction o# motion&to right (1) 1(iii) (t % s&v % =/*&*/0* %) J/* s (1) 1(iv) F % m (v u)&tR % J** - 1/+&J/*R % 1+* (3)ec& b (iii) (=) =
(d) Q % mc R so */K - =/2 - 1*1* - 2/. - 1* 1= % */**1 - 11* : (+)giving % */+1= L s 1R and t % 1& % '/2 s (+)or Q % mc R Q&L % */**1 - 11* % */11 _ L 1R (+)Q&s % */*+=' _R so t % */11&*/*+=' % '/2 s (+) '
[13]
75. Faraday9s law: the em#&voltage induced across a coil&component&circuit is (1) proportional to the rate o# change o# #luI (linkage) through it &5G (1)magnetic #luI % B5R (1)meanings o# B and 5 i/e/ #luI density or #ield strength and area (⊥ to it) (1)magnetic #luI linkage re#ers to the #luI linking&passing through a coilR (1)and e,uals 3 - #luI where 3 is the number o# turns o# the coil (1) maI JQuality o# Gritten !ommunication +
[7]
76. sine or cosine wave o# regular period and amplitude (1)4 doubles when the speed v o# rotation o# the coil doublesR (1)when v doubles the rate o# change o# #luI linking the coil doublesR (1)
the #re,uency o# the a/c/ signal doubles&period halves&5G (1)4 doubles when the number n o# turns on the coil doublesR (1)when n doubles there is twice as much #luI linking the coil&5GR (1)the #re,uency&period o# the signal is unchangedR (1)without iron core #luI linking coil is much less&#luI would spread in alldirections&#luI not channelled through low reluctance path&5G (1)amplitude o# output voltage is smaller (1)actually is tiny:negligible:mV rather than V maI 2Quality o# Gritten !ommunication +
density (very) much greater than material on $arth (1),uotes typical density on $arth 1 1*' kg m = (1)atomic structure collapsed & density same as atomic nucleus (1) +
[5]
79. (i) energies&temperatures irreproducible on $arth & laws o# Hhysics break down (1) 1 (ii) temperature decreases (1)
universe eIpanding&work done against attractive #orces& energyconverted to mass (1) +
(iii) an$ 3 #rom
protons and electrons separate initially (1)matterAradiation e,uilibrium&charge prevents passage o# em waves (1) protonAelectron recombination &#ormation o# atoms (1)gamma& em waves no longer absorbed (1) =
(d) n launch the rocket gives the spacecra#t a huge kinetic energy (in
order to escape)Failure at this point could cause spacecra#t and contents to burn upin atmosphereBut plutonium would still be radioactive and being vaporised it could be ingested/Sensible comment on danger periods o# launch (or reAentry)Sensible comment on mechanism o# ingesting Hlutonium5llow one sensible comment on no risks in the isolation o# deep space +
84. PAray (photons penetrate patient (1)attenuation by di##erent media & bones attenuate more than so#t tissue (1)less PAray reach #ilm under bone & shadow e##ect (1)intensity o# PArays is proportional to darkening o# #ilm & re#/ 6o #ogging or blackening (1)PAray photons hit crystals & atoms in intensi#ying layer (1)atoms become eIcited & #luorescence occurs (1)emitting light (photons) (1)detail : as they return to ground state (1)so eItra #ogging o# #ilm (1)detail : metal backing stops PArays passing through & #ilm more sensitive to lightthan PArays & most PArays pass through the #ilm & double sided & photographic#ilm & more contrast but not clearer (1)Cesponse is ,uicker & less PArays needed (1)so less eIposure (1)to axi # of 8 K
[8]
85. alternating voltage or alternating $A#ield across crystal (1)at resonant #re,uency (1) allow re#erence to resonance o# crystal +
[2]
86. (i) position o# = lower oIygen ions closer to positive plate (1) 1
(ii) re#/ to change in dimension & shape & distort& it gets longer (1) 1[2]
87. (a) (i) #or air is '+. (kg m + s 1) and #or skin is 1/21 - 1*0 (kg m +s 1) (1)
Substitution into e,uation leading to F % */... (1) + (ii) with gel more ultrasound enters body & without gel
most ultrasound is re#lected (1)most ultrasound is re#lected (without gel) when the di##erence in is largeor most ultrasound enters body when the di##erent in is small (1) +
s % vt or4080 - 1/J - 1* J (1)s % 0/1+ cm (1)ec& i& speed is wrong
&+ % =/*0 cm (1) '[8]
88. 5t least = #ield lines inside solenoid parallel to aIisR (1)Mines e,ually spaced over some o# length o# solenoid/ (1)5rrows on lines pointing le#t to right/ (1) =
[3]
89. (a) similar mass means large momentum trans#er (in collision)R (1)
hence #ewer collisions are neededR (1) +neutron colliding with heavy nucleus bounces o## with similar speed & k/e/scores 1&+ maI/neutron colliding with similar mass nucleus trans#ers large k/e/ & speedscores 1&+ maI/
(b) +=0.+" [ 11*
'J Ch 1+1'2 5g J1
*n (+)
allow+=J
.+" 1*n [
11*'J Ch
1+1'2 5g J
1*n
no neutrons *&+ incorrect number o# neutrons >J1
* 3 gets 1&+ maI/J*n gets *&+
i#1* missing #rom neutron symbol 1&+ maI/
+=0.+" 1
*n [ 11*'J Ch 1+1
'2 5g 01*n gets > +
[4]
90. neutron is udd & proton is uudR (1),uarks are: up down strange top bottom charmR (1)either up & u has; % ( )+&= < % ( )1&=Ror down & d has; % 1&= < % ( )1&=R (1),uarks are #undamental particlesR (1)#or every ,uark there is an anti,uarkR (1)anti,uarks have opposite values o#; < and= (compared to ,uark) (1),uarks are held together by strong #orce & gluons (1); < and= are conserved in (,uark) reactions (1)any ' J
93. (a) 3p graph: graph has eIponential shape & there is eIponential decay o# 3pnuclei & number (o# 3p nuclei) is halved in +/= days & constanttime & in its hal# li#eR (1)
Hu graph: sum o# Hu 3p nuclei % =/* - 1*+* at all timesR (1)either because one 3p nucleus decays to one Hu nucleusor rate o# decay o# 3p and #ormation o# Hu are e,ualR (1)and hal# li#e o# Hu & much bigger than hal# li#e o# 3pR (1) =
any ' (')
(b) time re,uired % time #or 3p nucleus to #all to */=* - 1*+*R (1)
t % 2/K days (1)or uses % * e /t where / % ln + & +/=0 (% */+.' day 1) (1)
so */1 % e */+.' t (1)ln (*/1) % */+.'t t % 2/K days (1)
or / % ln + & (+/=0 - +' - =0**) % =/'1 - 1* 0 s 1 (1)*/1 % e =/'1 - 1*eIp( 0) t ln (*/1) % =/'1 - 1* 0 t (1)t % 0/20 - 1*J s % 0/20 - 1*J & (+' - =0**) % 2/K days (1) '
calculates time #or 3p to #all to +/2 - 1*+* & Hu to rise to */= - 1*+* % */=0 daygets * 1 1 1 % =&'uses2 > #or plutonium can get +&' maI/attempts to use repeated halving o# can get +&' maI/ i# using */= (not +/2)
[7]
94. (a) e,ually spaced hori7ontal parallel lines #rom plate to plateR arrowstowards BR ,uality mark =
(b) Dydrogen and helium in early stars and sun 1Sun has greater proportion o# helium than early stars&D changed to De by #usion in sun/ 14irtually no higher elements in #irst stars& sun containstraces o# higher elements (accept speci#ic eIamples up to iron) 1
[4]
103. 5ny J #romred shi#t data #or galaIies (accept stars) 1calculate velocity #rom red shi#t 1galaIies& stars receding #rom $arth 1distance data #or galaIies& stars 1velocity @ distance & v&r % constant & vAr graph straight line 1universe began at a single point 1
[5]
104. (a) 5ny twostars rotate around galactic centre 1star with velocity component towards $arth 1re#erence to motion&shape o# galaIy 1or other valid points eg blue shi#t
(b) Do % 2J& = - 1*1.
s 1
1t ? 1& +/J - 1* 1K 1t ? ' - 1* 12 s 1
[5]
105. critical density is that #or #lat universe 1density p* universe closed&contracts&big crunch 1density p* universe open& eIpands #orever 1any + #rom#ate unknown because si7e&mass&density universe uncertain 1#ate unknown because p* & D* not known 1
(ii) original ratio +'* & +=. % '* - 1*+* &(J - 1*+*) % K (1)(ratio a#ter .*** years % ')e,ual numbers a#ter another .*** .*** % 1K*** years (1)so total time % .*** 1K*** % +2*** years (1) =
[12]
109. either number o# atoms o#'
+De in 1/* kg % (1 & */**') - 0/*+ - 1*+= (% 1/J1 - 1*+0) (1)so total energy % 1/J1 - 1*+0 - +K/' - 1/0 - 1* 1. - 1*0 (1)
113. (a) B % F& l with symbols eIplained or appropriate statement in wordsR (1)eIplicit re#erence to and B at right angles&de#ine #rom F % BQv etc (1) +
(b) (i) arrow towards centre o# circle 1
(ii) #ield out o# paperR Fleming9s M/D/ rule&moving protons act asconventional current +
114. @ helium nucleus X electron photon&eAm radiation&energy (1)@ charge (+e) mass 'm p&'u X charge (e) mass me charge * mass * (+)@ emission energy = 2 Ee4 X emission energy 1 + Ee4 emission energy about 1 + Ee4or all o# the same order o# magnitude&5G (1)@ monoenergetic #rom given nuclide X range o# emission energies #romgiven nuclide #rom 7ero to a maIimum monoenergetic #rom givennuclideor comparison in terms o# velocities (1)@ range = 2 cm o# air X range 1 + m o# air range inverse s,uarelaw in air& order o# kms (1)@ absorbed by paper X absorbed by thin& 1 mm 5l sheet up to cm o# Hb sheet (1)@ strongly ionising X weakly ionising hardly ionising at all (1)any other sensible comparison (1) 0
max # marks
Quality o# written communication +[8]
115. range&penetration&absorption&de#lection eIperiment suggested (1)but no &urther progress made to answer 1uestion otherwise+suitable arrangement and choice o# apparatusall can be shown on a diagram (+)
range&penetration&absorption eIperiment:@ place detector very close& +cm #rom sourceR measure count rate
use paper screen or move back to 1* cm or more measure count rateinterpret resultR contrast to background count level& other emissions#rom same source (=)
X place detector e/g/ 1* cm #rom source measure count rateadd thin sheets o# 5l until count drops to very low or almostconstant valueR interpret result (+)place detector e/g/ 1* cm #rom source measure count rateadd thin sheets o# Hb until count drops to very low&backgroundlevelR interpret result (+)max # marks
aliter de#lection eIperiment:needs vacuum #or @ eIperimentR (1)source #or radiation passes through region o# $A or BA #ieldR (1)de#lection or not o# particles detected by detector to distinguish emissionsR (1)
detail o# directionsRall 3 correct ' marks can only score maxo& % mark unless $acuum mentioned (+)amount o# curvature determines energy o# emissionRand nature o# particle (1)max # marks 0
116. Hlanets move in ellipses (Sun at one #ocus) (1)Hlanet sweeps out e,ual areas in e,ual times/ (1)Heriod+ @ radius= & 6+& r = % constant (1) =
[3]
117. (i) v&c % O & O (1)O % 0J0/= - 1* . - 0/1 & = - 1*K (ignore minus sign) (1)O % 1/== - 1* 1' m (1) =
(ii) Yraph: any ' points plotted correctly (1)
all correct (1) + (iii) graph: draw curve reasonable attempt (1) 1(iv) $ither point where star moves perpendicular to line o# sight (1) 1 (v) time % 2+ h W (1)h (ec# read value #rom their graph W 1 h) (1) 1
123. 'n$ 2 fro 3o eIperimental evidence& no physical evidence (1)State o# matter unknown& laws o# physics unknown (1)$nergies unreproducible& re#/ to very high temperature (1) +
[2]
124. pen: "niverse eIpands #or all time (1)Flat: eIpands to a limit (but never reaches it) (1)!losed: "niverse contracts& collapses back (1)re#erence to role o# gravity& critical density (1)Earks #or a/ can be gained on labelled diagram/ '
[4]
125. Do+ % 1 - 1* +0 - K - - 0/02 - 1* 11 & = (1)
Do % +/=0 - 1* 1K s 1 (1) +[2]
126. 1 each to a axi # of 7&
$lectrons are emitted #rom ! & (hot) cathode/6here is a high voltage between ! and 5 / or stated p/d/ 1*** 4
(so) electrons are accelerated towards 5 & anode/$lectrical energy becomes L$ (o# electron)/$lectrons undergo a sudden deceleration at 5 & collide with 5(Some o#) the L$ is converted to PArays & (electromagnetic) radiation6he PArays are produced by the deceleration & re#erence to bremsstrahlungPArays characteristic o# target produced)/
Eost o# the (kinetic) energy becomes heat & thermal energy/6he reason #or the vacuum/
ther good point (eg anode rotated & inner shell electron o# target atomknocked out & higher pd gives more penetrating PArays&higher energy photons)/ 2
[7]
127. (a) Mow energy PArays are absorbed by the skin & undesirable as can causedamage & greater ionising (1) 1
(i) and (ii) +1** as #irst #igure to be #illed in #or nuclide) (1)1002 (1)1*J* (1)idea o# subtraction #or nuclide* (1)correct values #or the ones given in nuclide* column (1) J
(c) sensible graph plotted (1)
eItrapolation done (1)value 2* W J hours (1) =
C , % , * e Ot (1)ln , % ln , * /t e/g/ when , % +.0 t % =* hJ/0.*' % J/..1J / - =* (1)*/=*11&=* % */*1**' % /O % ln +& / % 0./* h answers will vary slightly dependent on starting and#inishing times (1)
(d) separate the two nuclides (be#ore starting the count) (1) by chemical means (i# possible) (1) +
C using a centri#uge or di##usion (i# isotopes)C sensible idea about shielding against one o# the emitted particles
(e) decay constants or hal# lives are di##erent (1)
hal#Ali#e at the start is approIimately that #or) (1)) decays more rapidly than* so a#ter a long time the hal#Ali#e is that #or* (1)in between it has a value intermediate between the two (which varies) (1) =
D,EFDGD 3
C dealt with mathematically along the lines o# two separate eIponential decays (1)when added together do not give an eIponential graph (1)with back up maths (1)