Module 5 : MODERN PHYSICS
Lecture 26 : Wave Nature of Particle - the de Broglie Hypothesis
 
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  A beam of electrons from a heated filament, accelerated through a potential difference $ V$ is made to strike the surface of a crystal of Ni. Electrons are scattered in all directions and may be detected by an array of detectors located at various angles of scattering. It is found that the intensity of scattered beam is maximum at some particular angles of incidence, in the same manner as the case when a beam of x-rays strikes the crystal
  In Davisson - Germer experiment, the electron beam was accelerated through a potential difference of $ V=54$ volts. The kinetic energy $ E$ of the electron is thus 54 eV. The de Broglie wavelength associated with an electron accelerated through a potential difference $ V$ may be expressed as
 
$\displaystyle \lambda = \frac{h}{p}= \frac{h}{\sqrt{2mE}}= \frac{h}{\sqrt{2meV}}$
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