Question
Fri March 28, 2014 By: Navdeep Bhardwaj

IN THE PHOTOELECTRIC EFFECT , I WANT TO ASK THAT .....IS THE ENERGY OF INCIDENT PHOTON AND RELEASED ELECTRON  SAME OR NOT ???? 

Expert Reply
Tue April 01, 2014
?????It depends upon the material from which the photoelectrons emit.
The energy of released electron is not the same as that of the energy of incident photon.
The incident photon have a characteristic energy corresponding to its frequency and it is used by the electron to escape from the surface of the material.
 
if the energy of incident photon corresponds to the work function of the material, the electrons takes up the energy of incident photon to get out of the material.
If the energy of incident photon is less than the energy required for the emission of electrons (or work function of material) No photoemission occurs.
If the energy of incident photon is greater than the work function of the material ,electrons are emitted with a kinetic energy equal to the excess energy.
Hency the energy of incident photon, hν = φ (work function of material) + Kinetic energy of electron.
The energy of incident photon is used up for the ejection of electrons and if its greater than the workfunction of the material the released electron aquires a kinetic energy corresponding to the excess energy else the electrons get emittted without any K.E.
 
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