ISO 9001:2015Made in INDIA


Fresnel's Biprism Diffraction Apparatus
Model: HO-ED-D-07
Price : $ 1,275.00

Holmarc's Fresnel's biprism diffraction Apparatus (Model No: HO-ED-D-07) 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.

The apparatus consists of an optical rail on which components are mounted using posts, post holders and movable carriages. For setting up the experiment, the slit, eye piece and the biprism are adjusted so as to obtain well defined bright and dark fringes. Sodium vapour lamp is used as light source. All components are made out of anodized aluminum and stainless steel to avoid corrosion.

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 diverging 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. Students gain knowledge of the general setup of the Fresnel experiment and the interference patterns. Research quality modules of the instrument can be used for project works as well.

More +


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

(λ = β d / D)

Scope of Supply

Optical Rail

Model No: ED-D-07-OR
Length : 1500 mm
Material : Aluminum alloy
Finish : Black anodized
Quantity : 1 no.

Slit with Mount

Model No: ED-D-07-SM
Controlling : Lead screw
Slit Size : 0 - 3 mm
Quantity : 1 no.

Bi Prism Mount

Model No: ED-D-07-BM
Controlling : Lead screw
Dial movement Course : 360 degree
Fine : 10 degree
Quantity : 1 no.

Achromatic Lens with Mount

Model No: ED-D-07-ALM
Focal length : 197.5 mm
Diameter : 40 mm
Material : BK7
Quantity : 1 no.

Eye Piece with Micrometer Drive

Model No: ED-D-07-EPM
Micrometers : 2 nos.
Least Count : 0.01 mm
Quantity : 1 no.

Screen with Mount

Model No: ED-D-07-SM
Material : Acrylic
Size : 200 x 150 mm
Quantity : 1 no.

Bi Prism

Model No: ED-D-07-BP
Material : BK7
Quantity : 1 no.

Sodium Vapor Lamp with Power Supply

Model No: ED-D-07-SLPS
Output Power : 35 W
Quantity : 1 no.


User Manual


Established in 1993, Holmarc Opto-Mechatronics Ltd manufactures variety of scientific and engineering instruments for research, industry and education.

ISO 9001:2015 Made in INDIA

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    B.7., H.M.T. Industrial Estate H.M.T. P.O, Kalamassery, Kochi Kerala, India - 683 503
   +91 0484 2953780 / 0484 2953781
   Mon - Sat : 9 am to 5 pm

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