Description

Fresnel’s biprism diffraction Apparatus is an instrument that demonstrates how Fresnel’s Bi prism can be used to obtain fringes due to interference and to calculate the wavelength of monochromatic light. Bi-prism produces interference pattern from a single source due to the creation of two virtual coherent sources as the light passes through the prism.

Fresnel’s biprism consist of two prisms of very small angles joined base to base. In practice, a thin glass plate is taken and one of its faces is ground and polished till a prism is formed with an obtuse angle of about 179° and two side angles of the order 30 arc minutes. If a beam of light strikes the edge of the biprism, two diverging coherent light beams are created which appear to emerge from two virtual slits and interfere on the far side of the biprism.

Experiment Performed

• To find the wavelength of the sodium light using bi-prism diffraction experiment

Feature

• Compact and integrated design
• Sodium vapor lamp as light source with light output port adjustable in length
• Precision lead screw driven slit provided with a maximum opening of 3mm
• Eyepiece with micrometer drive for achieving perfect linear motion
• Precision rotary coarse and fine adjustments with lead screw controller in biprism mount
• Achromatic lens is used for focusing image