Hey there! Sign in to join this conversationNew here? Join for free
    • Thread Starter
    Offline

    0
    ReputationRep:
    'Explain why the emitted electrons have a range of kinetic energies up to a maximum value'

    I just don't get it
    Offline

    11
    ReputationRep:
    (Original post by 3607)
    'Explain why the emitted electrons have a range of kinetic energies up to a maximum value'

    I just don't get it
    Hard to give a hint really, so I'll just tell you what my teacher told me:
    Spoiler:
    Show
    Not all the photoelectrons ejected are from the surface of the metal, these require more energy to overcome the attractions of the lattice to be ejected.
    • Thread Starter
    Offline

    0
    ReputationRep:
    So stuff deeper in needs more energy to release it?
    Offline

    16
    ReputationRep:
    The work function is the minimum energy required for photoelectric emission. When individual photons of monochromatic light with energy E=hf interact with individual electrons they transfer all their energy . Those electrons that are held least tightly only require enough energy to overcome the work function to escape and as a result leave with maximum kinetic energy remaining. Some electrons are held more tightly and must use more energy in emission resulting in smaller values for their kinetic energy.
    • Community Assistant
    Offline

    20
    ReputationRep:
    Community Assistant
    (Original post by 3607)
    So stuff deeper in needs more energy to release it?
    essentially yes, another reason is that the dipoles in the metal change orientation rapidly and so some electrons will experience a stronger pull from the metal and require more energy to eject - the work function of the metal is the absolute minimum required for a photoelectron to be ejected.
    Offline

    17
    ReputationRep:
    (Original post by 3607)
    'Explain why the emitted electrons have a range of kinetic energies up to a maximum value'

    I just don't get it
    For the emission of electrons the work function of the metal needs to be overcome. Once the electron has gained sufficient energy, either by interaction with another electron or by absorbing a photon, the electron is excited. Electrons which have lots of energy use some of the energy as kinetic energy. If an electron is being removed from deeper within the metal, it will have less kinetic energy because more work is done to push the electron to the surface of the metal, from where it can be emitted. Electrons that are on the surface of the metal will have more energy because they don't use any of their energy to push their way through the metal because they are already on the surface.
    Therefore electrons can have a range of kinetic energies.
    Hope that helped!
    • Peer Support Volunteers
    • Clearing and Applications Advisor
    • Study Helper
    Offline

    19
    Peer Support Volunteers
    Clearing and Applications Advisor
    Study Helper
    (Original post by Nav_Mallhi)
    Once the electron has gained sufficient energy, either by interaction with another electron or by absorbing a photon, the electron is excited.
    Don't get confused between excitation and the photoelectric effect.
    Offline

    17
    ReputationRep:
    (Original post by usycool1)
    Don't get confused between excitation and the photoelectric effect.
    I know the difference but excitation is a part of the photoelectric effect right? The electrons have to be excited in order to the emission of electrons to occur. Am I right?
    • Thread Starter
    Offline

    0
    ReputationRep:
    Thanks to everyone I'm hoping I can somehow scrounge a B out of physics, I don't get how people are so good at it Fair play to you if you are though, hardest thing I've ever done.
    • Peer Support Volunteers
    • Clearing and Applications Advisor
    • Study Helper
    Offline

    19
    Peer Support Volunteers
    Clearing and Applications Advisor
    Study Helper
    (Original post by Nav_Mallhi)
    I know the difference but excitation is a part of the photoelectric effect right? The electrons have to be excited in order to the emission of electrons to occur. Am I right?
    The photoelectric effect can only happen if photons with sufficient energy are absorbed by electrons in the metal. It doesn't really have anything to do with electron collision or interaction, as you said in your previous post.
 
 
 
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • Poll
    Has a teacher ever helped you cheat?
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

    Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

    Write a reply...
    Reply
    Hide
    Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.