Immagini

DESCRIPTION

Exhibit 411 is an apparatus for observing the diffraction of a wire, which according to the principle of Babinet is identical to that produced by a slit with the same form and dimension. The wire should be thin (50-100 microns) because the diffraction pattern is clear if the dimension of the obstacle is comparable to the wavelength of the incident light. The wire is mounted in the center of a rectangular opening in a brass disk mounted on a brass support. A lamp can be placed on the top and its light is reflected in the mirror on the back side to illuminate the wire. The diffraction pattern is then visible on a screen placed on the front side.

The diameter of the wire (d) is given by the formula (vedi Design-1):

where
D = distance between the wire and the screen;
λ = wavelength of the employed light;
x = distance between two minimum intensity fringes (dark area), one on each side of the central light fringe.

BIBLIOGRAPHY

• [1] URL [ http://people.na.infn.it/~abete/Materiale_LDFM/scheda_capello.pdf ]

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