Fresnel biprism

Fresnel's Biprism experiment for engg ppl

1. To Determine the wavelength by using sodium lamp and by Fresnel biprism action .

2. *optical bench * biprism *Convex lens *Sodium vapour lamp *Slit *Micrometer eyepiece Apparatus :

3. λ = β d D where, λ – wavelength of light, β – fringe width, d- the distance between two virtual sources formed by biprism , D- the distance between the slit and the eyepiece. FORMULA:

4. Experimental diagram :

5. Ray diagram -►

6. Measurement of ‘d’ -►

7. Slit ( source) Biprism ( two virtual souse) Stand for lens Optical bench Whole setup foe deterring the wavelength of sodium ligh by Fresnel's biprism

8. Whole setup for determining the diameter of wire by using difrraction in shadow region phenomenon:- source slit Stand for wire Screen or eyepiece

9. Screw to setup the slit axis ( i.e. parallel to wire) Slit opening Screw to adjust the width of the slit Screw to adjust the height of the slit SLIT:-

10. Screw to adjust the axis of Biprism Screw to inset the Biprism properly Biprism Screw to adjust the height of the biprism Tangent screw (to remove the lateral shift of the fringe pattern). Biprism stand:-

11. Screw to adjust the axis of the wire Wire to measure the diameter Screw to fit the wire stand Optical bench Tangent screw. Wire Stand:-

12. Micrometer reading Screw to rotate the micrometer Ramsden’s eyepiece( screen to see the fringes) Main scale reading Screw to adjust the upright position of screen. Screen:-

13. To remove the bench error:- slit Measuring rod stand

14. How to remove the bench error:- first of all measure the length of rod by optical bench and by scale both. scale measure the actual length and optical bench measure the apparent one. then find the error. Precautions:- Always first remove the lateral shift then onwards perform the experiment.