AQA A LEVEL PHYSICS PAPER
QUESTIONS AND REVISED ANSWERS *_EDITED EDITION
What is meant by work function (2) - AnswerMinimum energy required by an electron to
escape from (1) a metal surface (1)
What is meant by ionisation energy? (2) - AnswerMinimum energy required to remove an
electron from an atom (1) from the ground state (1)
Why do emitted electrons have a kinetic energy that varies up to a maximum value? (4) -
AnswerEnergy of a photon is fixed/constant (1)
Energy is required for electrons to overcome work function ø (1)
Electrons deeper into/below the surface of the metal require more energy to overcome
work function and therefore have less KE(1)
Maximum KE = Energy of photon - work function ø (1)
Explain how (bright ring) diagram is evidence of the wave-particle duality of electrons? -
AnswerDiffraction pattern maxima/minima (bright and dark areas) (1)
Diffraction is a property of waves- proves wave-behaviour of electrons (1)
What is meant by the ground state? - AnswerThe lowest energy state of an atom
Explain the difference between excitation and ionisation (2) - AnswerAn electron receives a
discrete amount of energy for BOTH (1)
Excitation promotes an electron to a higher energy level
Ionisation is when an electron receives enough energy to leave the atom
, Explain why only photons of certain frequencies cause excitation (4) - Answerdiscrete energy
levels (1)
Electrons need to absorb a DISCRETE amount of energy to move to a higher energy level (1)
Photons need to have a certain frequency to provide this energy, because E=hf (1)
interaction is a 1:1 reaction all of the photon's energy is absorbed (1)
Explain CChow CCexcitation CCtakes CCplace CCin CCa CCfluorescent CCtube CC- CCAnswerElectrons CCflow
CCthrough CCthe CCtube CCto CCthe CCapplied CCPD CCcausing CCa CCcurrent CCto CCflow CC(1)
Electrons CCcollide CCwith CCmercury CCatoms CCin CCthe CCtube CC(1)
This CCraises CCelectrons CCin CCthe CCmercury CCatom CCto CCa CChigher CCenergy CClevel CC(1)
What CCis CCthe CCpurpose CCof CCcoating CCin CCa CCfluorescent CCtube? CC- CCAnswerUV/ CCHigh CCenergy
CCphotons CCemitted CCfrom CCmercury CCatoms CCwhen CCthe CCelectrons CCin CCthe CCatom CCde-excite
CC(1)
High CCenergy CCphotons CCabsorbed CCby CCthe CCcoating CC(1)
Coating CCemits CCphotons CCin CCthe CCvisible CCspectrum CC(1)
What CChappens CCwhen CCannihilation CCoccurs? CC(2) CC- CCAnswerparticle CCand CCan CCanti-particle
CCcollide CCand CCcease CCto CCexist CC(1)
Their CCmass CCis CCreleased CCas CCenergy CCin CCthe CCform CCof CCa CCpair CCof CCgamma CCphotons CC(1)
How CCdoes CCthe CCstrong CCnuclear CCforce CCbetween CCtwo CCnucleons CCvary CCwith CCthe CCseparation
CCof CCthe CCnucleons? CC(3) CC- CCAnswerrepulsive CCat CC< CC0.5 CCfm CC(1)
attractive CCfrom CC0.5 CCto CC3 CCfm CC(1)
CC
above CC3 CCfm, CCforce CC0 CC(1)
What CCis CCmeant CCby CCmonochromatic CClight CC- CCAnswerlight CCof CCa CCsingle CCfrequency
What CCis CCmeant CCby CCcoherent CC- CCAnswerconstant CCphase CCdifference
QUESTIONS AND REVISED ANSWERS *_EDITED EDITION
What is meant by work function (2) - AnswerMinimum energy required by an electron to
escape from (1) a metal surface (1)
What is meant by ionisation energy? (2) - AnswerMinimum energy required to remove an
electron from an atom (1) from the ground state (1)
Why do emitted electrons have a kinetic energy that varies up to a maximum value? (4) -
AnswerEnergy of a photon is fixed/constant (1)
Energy is required for electrons to overcome work function ø (1)
Electrons deeper into/below the surface of the metal require more energy to overcome
work function and therefore have less KE(1)
Maximum KE = Energy of photon - work function ø (1)
Explain how (bright ring) diagram is evidence of the wave-particle duality of electrons? -
AnswerDiffraction pattern maxima/minima (bright and dark areas) (1)
Diffraction is a property of waves- proves wave-behaviour of electrons (1)
What is meant by the ground state? - AnswerThe lowest energy state of an atom
Explain the difference between excitation and ionisation (2) - AnswerAn electron receives a
discrete amount of energy for BOTH (1)
Excitation promotes an electron to a higher energy level
Ionisation is when an electron receives enough energy to leave the atom
, Explain why only photons of certain frequencies cause excitation (4) - Answerdiscrete energy
levels (1)
Electrons need to absorb a DISCRETE amount of energy to move to a higher energy level (1)
Photons need to have a certain frequency to provide this energy, because E=hf (1)
interaction is a 1:1 reaction all of the photon's energy is absorbed (1)
Explain CChow CCexcitation CCtakes CCplace CCin CCa CCfluorescent CCtube CC- CCAnswerElectrons CCflow
CCthrough CCthe CCtube CCto CCthe CCapplied CCPD CCcausing CCa CCcurrent CCto CCflow CC(1)
Electrons CCcollide CCwith CCmercury CCatoms CCin CCthe CCtube CC(1)
This CCraises CCelectrons CCin CCthe CCmercury CCatom CCto CCa CChigher CCenergy CClevel CC(1)
What CCis CCthe CCpurpose CCof CCcoating CCin CCa CCfluorescent CCtube? CC- CCAnswerUV/ CCHigh CCenergy
CCphotons CCemitted CCfrom CCmercury CCatoms CCwhen CCthe CCelectrons CCin CCthe CCatom CCde-excite
CC(1)
High CCenergy CCphotons CCabsorbed CCby CCthe CCcoating CC(1)
Coating CCemits CCphotons CCin CCthe CCvisible CCspectrum CC(1)
What CChappens CCwhen CCannihilation CCoccurs? CC(2) CC- CCAnswerparticle CCand CCan CCanti-particle
CCcollide CCand CCcease CCto CCexist CC(1)
Their CCmass CCis CCreleased CCas CCenergy CCin CCthe CCform CCof CCa CCpair CCof CCgamma CCphotons CC(1)
How CCdoes CCthe CCstrong CCnuclear CCforce CCbetween CCtwo CCnucleons CCvary CCwith CCthe CCseparation
CCof CCthe CCnucleons? CC(3) CC- CCAnswerrepulsive CCat CC< CC0.5 CCfm CC(1)
attractive CCfrom CC0.5 CCto CC3 CCfm CC(1)
CC
above CC3 CCfm, CCforce CC0 CC(1)
What CCis CCmeant CCby CCmonochromatic CClight CC- CCAnswerlight CCof CCa CCsingle CCfrequency
What CCis CCmeant CCby CCcoherent CC- CCAnswerconstant CCphase CCdifference
