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level: Wave particle duality

Questions and Answers List

level questions: Wave particle duality

QuestionAnswer
what is photoemissiona process during which electrons are ejected from a metal surface when exposed to electromagnetic radiation (eg ultraviolet)
under what conditions will electrons be liberated from a plateif the plate is negatively charged if the source is of a high enough frequency
what does intensity of a source affectthe time taken for a negatively charged plate to discharge (as electrons are liberated)
does the total amount of energy from the source determine whether the plate discharges or notno
what are beams of light and ultraviolet made ofindividual units called photons
what must each photon have before an electron can be removed from a negatively charged plateenough energy to remove the electron
what evidence is there that electrons are liberated and not photonsphoto emission only occurs from negatively charged surfaces. The negative charge decreases when this happens, which indicates that negatively charged electrons are leaving the surface
what does the energy of a photon depend onits frequency
what does whether photoemission takes place or not depend onthe energy of the photon the type of metal being tested
what is the equation relating energy of a photon to its frequencyE=hf E is the energy of the photon h is plancks constant f is the frequency of the radiation
what is plancks constant6.63x10^-34
what is threshold frequency (fo)the minimum frequency required to cause photoemission
what is the work function (W)the minimum energy required to remove an electron from a metal
what is the equation relating work function and threshold frequencyW=hfo where W is work function h is plancks constant fo is threshold frequency
do different metals have the same or different work functionsdifferent this means it is easier to remove electrons from some metals than others, therefore the minimum frequency of a photon needed to remove an electron from one mtal can be lower than for another metal
what is the relationship between work function and threshold frequencythe lower the work function the lower the threshold frequency
when an electron is ejected from a metal surface what kind of energy does it havekinetic energy
what does the amount of kinetic energy an electron being ejected form a metal surface depend onthe difference between the energy of the photon and the work function of the metal
give an equation that relates kinetic energy, work function of metal and energy of photonEk = E - W where Ek is kinetic energy of the electron E is the energy of the photon W is the work function of the metal OR Ek=hf-hfo Ek=h(f-fo)