• Subject:


  • Topic:


(i) Name the experiment which confirms the existence of wave nature of electrons. Derive the experience for de-brogile wavelength of an electron moving under a potential difference of V volts. (ii) An electron and a proton have the same kinetic Energy. which of these particles has the shorter de-broglie wavelength?


(i) Davisson - Germer experiment

       An electron of charge e, mass m acclerated through a potential difference of v volts, Kinetic energy equals the work done (eV) on it by the electric field:

K=eV                                                        K= p22m =(2mk)                       p=(2meV)  the de-Brogile wavelength λ of the electron is: λ=hp                                                     λ=h(2mev)                                                   

(ii) For same KE, λ a 1m

As mass of proton is greater than that of electron, so λp<λe.             (1/2) marks