» Variable rectangular Slit (0591)

Immagini

DESCRIPTION

Exhibit 591 is a rectangular slit of length 10 mm composed of two identical parts each of length 5 mm and independently variable. They are mounted in a mechanical system of springs and gears controllable by means of two knobs that vary the widths of the two parts. Each knob is graduated in microns, one with an index and the other with a vernier.

Remembering that the necessary condition for observing diffraction effects is that the width dimension of the slit must be of the order of the wave length of the incident light, the device can be used to demonstrate: (vedi Ref ^[1]):

for a given slit width, the width of the spectrum is proportional to the wave length of the incident light. For example, the spectrum for red light is approximately twice as wide as for violet light.
for a given wave length, the angular size of the spectrum is inversely proportional to the slit width. (See Design-1).

The two parts can be used simultaneously to produce a more intense spectrum than either one alone. See also exhibit 770.

ISCRIZIONI

È inciso su un lato: "Symmetrisch A. Kruss Hamburg".
La parola Symmetrisch non è ben leggibile.

BIBLIOGRAPHY

[1] Jenkins and White, "Fundamentals of Optics", McGRAW-HILL Book Company, Inc. Third edition, 1957, Chapter 15, pagina 288
[2] URL [ http://hyperphysics.phy-astr.gsu.edu/HBASE/PHYOPT/sinslitd.html#c1 ]

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