Fresnel Biprism Interference Experiment

Fresnel's Biprism used to create two Virtual coherent light sources by refraction and reflection respectively and observe interference phenomenon. Monochromatic light in these experiments is produced by sodium light source or he-ne laser. The wavelength (λ) can be determined by the formula

Features:

• Heavy, rigid and stable Optical bench (made of Al extrusion)
• Fine adjustment of micrometer eye piece using micrometer scale.
• Saddle can hold rod from 8 to 15mm.
• Height and level adjustment screws (made of SS)
• Brass self centring slit.
• Universal clamp with 0 to 360° rotation.
• 10x eye piece provides better resolution

Learning Objectives/experiments

• To determine the wavelength of monochromatic light source from measuring the distance of the interference pattern.
• To observe two beam interference of two virtual light sources created at a biprism.
• To observe the image of virtual light sources and measuring their distance.
• To determine the prism angle.

Technical Data:

• Optical bench : Al exclusion, L = 1.5 mtr. with Scale, Triangular shape with end stop, 4 point levelling (steel screw)
• Fresnal’s Biprism : 50 x 40 mm (L x H), angle 179 , refractive index 1.52
• Slit : 0 – 6mm
• Lens : FL 100mm, 200mm, dia. 50mm
• Optics holder : Al, Dia. 130 x 3mm (Ø x T), H 230mm
• Universal holder : 3 point clamp (0 – 90 – 180), 0-360
• Micrometer : 30-0-30 mm, ½ least MSD
• Eye piece : 10x zoom, 31 x 23mm (L x Ø)
• Least count : 0.005 mm
• Sodium source : MS housing, 200 x 85mm (L x Ø), slit ( L x W) 20 x 16mm
• Lamp power : 20W, input 220V AC
• Transversal slider : 25 – 0 – 25mm, LC 0.01mm

Scope of Delivery:

• 1 Fresnel biprism
• 1 Universal lens holder (Biprism)
• 1 Optical bench triangular
• 1 Adjustable slit self centering
• 1 Sodium light source
• 1 Micrometer eyepiece
• 1 Convex lens in holder (FL 200mm)
• 1 Transverse slider
• 1 Fixed slider
• 1 Convex lense in holder (FL 100mm)

Key Topics:

• Interference
• Fresnel biprism
• Coherent sources by reflection
• Virtual coherent source by reflection refractive index
• Wave length
• Virtual light source