Davission and Germer Experiment

The de-Broglie suggested that every moving particle has a wave associated with it.

Davission and Germer experimentally proved that fast moving electron(particle) show diffraction, which is a property of of wave.

Experimental Setup and Construction:

It consists of an electron gun which compares of a tungsten filament F, coated with barium oxide and heated by a low voltage power supply. Electrons emitted by the filament are associated to a desired velocity by applying suitable potential from a high voltage power supply.

They are made to pass through a cylinder with free holes along its Axis, producing a fine collimated beam. The beam is made to fall on the surface of a Nickel crystal. The electrons are scattered in all directions by the atom of the Crystal, which cut along cubicle Axis at a particular angle.

The scattered beam of electrons is received by the detector which can be rotated at any angle and it connected with a galvanometer.


When incident beam of electron passes through cylinder, it can accelerate by using HT voltage and strikes on Nickel crystal, and scattered in all the directions. The intensity of the electron can be measured by movable detector.

The experiment was performed with different accelerating potential(V) by HT, but significant intensity of electron was observed around 44 V to 68 V.

At 54 V HT accelerating potential, the intensity of electrons show a peak at Ø= 50⁰.

The peak indicates a constructive interference among electron was resulting a maximum intensity.

Calculation of Wavelength:

Davission and Germer Experiment

Davission and Germer Experiment
Davission and Germer Experiment

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