Sunday, 18 September 2011

Photoelectric Effect

What is Photoelectric Effect?
        
        In some of their experiments Sir J.J Thomson and P.Lenard showed that when a beam of light of suitable wavelength or frequency is allowed to fall on the surface of a metal, the electrons are emitted (or ejected) from the surface of metal. This phenomenon of emission of electrons is known as photoelectric effect or photoelectric emission (photo means light). Although the electrons emitted from the surface are no different from all other electrons, it is customary to call these electrons as photoelectrons.

        It may be noted that only a few metal can eject electrons when radiations from visible (which has less energy and hence is less energetic) fall on them, but many more metals are very much capable of ejecting electrons when a radiations from ultraviolet light (which has more energy and hence is more energetic) fall on them.




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