Monday, February 4, 2008

JEE Revision - de Broglie hypothesis

de Broglie hypothesis

Wave nature of light could not explain the photoelectric effect. Einstein has suggested that light can behave as a wave as well as a particle i.e., it has dual character. In 1924, de-Broglie extended the wave nature to matter. He suggested that all microscopic particles such as electrons, protons, atoms and molecules have dual character similar to light.

Thus according to de Broglie hypothesis, “all material particles in motion possess wave characteristics.”

The wavelength(λ), mass of the particle (m) and velocity (v) of the particle are related to each other by the relation

λ = h/mv

h = Planck’s constant = 6.63 *10^-34 kg m² s^-1

The equation was experimentally verified by Davisson and Germer.

The wave like chacter of electron helped in making electron microscope. The electron microscope utilizes the wave like behaviour of electrons.

The dual nature of matter is applicable to all material objects but it is significant for microscopic bodies only. For bigger bodies, wave lengths calculated using the above formula are so small that they have no significance.

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