Name: Matter Waves: G.P Thomson’s Experiment
Uploaded: 2019-07-19
Duration: 4 min 52 s
Description: After the experiments on diffraction of electrons by C. J. Davisson and L. H. Germer, G. P. Thomson also performed the experiment on electron diffraction. Le...

Question

Explain Davisson and Germer's experiment to show the wave nature of fast moving electrons by using the relation

λ = \sqrt{\frac{150}{V}} \overset{o}{A}

, where

λ

is wavelength and

V

is accelerating voltage.

Accepted Answer

The Davisson and Germer's experiment confirms the wave nature of electrons. The experimental arrangement for the experiment is shown in the diagram below:

The electrons emitted by the filament are accelerated to a desired velocity by applying suitable voltage. The collimated beam of electrons is made to fall on the surface of the nickel crystal. The electrons are scattered in all directions by the atoms of the crystal. The intensity of the electron beam in a given direction is measured by an electron detector. The detector is connected to a galvanometer which records the current. Hence, the defection of the galvanometer is proportional to the intensity of the electron beam. The experiment was performed by varying the accelerating voltage from $44 V$ to $68 V$ . A strong peak in the intensity of scattered electrons appeared for an accelerating voltage of $54 V$ . The appearance of the peak in a particular direction is due to the constructive interference of the electrons scattered from different layers of the crystal. From the electron diffraction measurements, the wavelength of the matter waves was found to be $1.65 \overset{\circ}{A}$ .

On using the given relation, the de Broglie wavelength associated with electrons for $V = 54 V$ :

$λ = \sqrt{\frac{150}{V}} = \sqrt{\frac{150}{54}} = 1.67 \overset{\circ}{A}$

It shows there is an excellent agreement between the experimental value and the theoretical value of the wavelength associated with the electrons. Hence, it confirms the wave nature of electrons.

Explain Davisson and Germer's experiment to show the wave nature of fast moving electrons by using the relation $λ = \sqrt{\frac{150}{V}} \overset{o}{A}$ , where $λ$ is wavelength and $V$ is accelerating voltage.

Important Questions on Matter Waves

Learn and Prepare for any exam you want !

Explain Davisson and Germer's experiment to show the wave nature of fast moving electrons by using the relation λ=150V Ao, where λ is wavelength and V is accelerating voltage.

Important Questions on Matter Waves

Learn and Prepare for any exam you want !

Explain Davisson and Germer's experiment to show the wave nature of fast moving electrons by using the relation $λ = \sqrt{\frac{150}{V}} \overset{o}{A}$ , where $λ$ is wavelength and $V$ is accelerating voltage.