Fresnel's Biprism experiment for engg ppl

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

3. λ = βd
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.

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.