name the exp which shows the wave nature of an electron? which phenomenon was observed in this exp using electron beam.?
The experiment that shows the wave nature of electron is Davisson and Germer experiment.
Davisson and Germer made some interesting observation in their experiment. While increasing the accelerating voltage of the electron beam definite peak intensity was observed at a particular voltage. This voltage was found to be 54 volts exactly. The peak cannot be explained by momentum exchanges in electron collisions. The only logical explanation is the constructive interference of electrons scattered from different layers of the crystal. Definitely a wave property.
The De Broglie wavelength associated with this voltage is 0.167 nm. This was exactly the wavelength found theoretically by De Broglie for electron matter waves.
This is how Davisson and Germer experiment explained the wave nature of electron and also found the wavelength associated with the electron as obtained by de Broglie relation.
In 1925 Clinton Davisson and C.H. Kunsman (later also Laster Germer) begun to conduct the experiments which confirmed the de Broglie's theory. They shot the crystal of nickel with a beam of electrons from the glowing cathode. That caused a secondary emission of electrons from the crystal. The number of the electrons sent in different directions was defined using the collector - a metal plate which incidencing electrons. The collector could have been moved around the crystal. By the accident the one of the nickel plates oxidised. To remove nickelic peroxide the plate was heated. After that the plate was used again in the experiment. But the results occurred to be completely different than before. That was because the method of cleaning the plate changed it in a big monocrystal. The electrons were emit from such plate in all directions but at some angles the emission was bigger. For the beam of electrons of the energy of 54 MeV the angle of the increased emission was equal about 500.
The angles at which the diffraction maximums occur can be calculated knowing the wave length and the construction of the diffraction grating. From the other hand the wave length can be calculated knowing the angles of the maximums and the characteristic of the grating. The wave length calculated by the scientists was equal 1,65*10-10 m. According to the de Broglie's wave theory the wave length of the electron when the wave is of the energy of 54 MeV is equal 1,67*10-10 m. Conformity of the two values confirmed the wave structure of the electron.