A flint glass and a crown glass are fitted on the two slits of a double slit apparatus The - Physics - Wave Optics

Question

A flint glass and a crown glass are fitted on the two slits of a
double slit apparatus The thickness of the strips is 0 40 mm and
the separation between the slits is 0 12 cm The refractive index of
flint glass and crown glass are 1 62 and 1 52 respectively for the
light of wavelength 480 nm which is used in the experiment The
interference is observed on a screen a distance one meter away
(a) What would be the fringe-width?
(b) At what distance from the geometrical centre will the nearest
maximum be located?

Find the thickness of a plate which will produce a change in
optical path equal to one fourth of the wavelength λ of the
light passing through it normally The refractive index of the plate
is µ

Ravi Gupta · Accepted Answer

Dear Student

Kindly find the answers of your asked query

Since after passing through the two materials wave length of light will remain same and value of D and d will als remain sameand fringe width β is given by:β=λDdhence fringe width will remain same
now fringe shift from the centre due to the upper slitis y1=βλμ-1t this is for flinty1=Ddμ-1t=1000
121 62-1×0 4 mm=206
66 mmthis shift is towards upwardnow fringe shift from the centre due to the lower slitis y1=βλμ-1t this is for crowny1=Ddμ-1t=1000
121 52-1×0 4 mm=173
33 mmthis shift is towards downwardso net fringe shifty = 206
66-173 33=33
33 mm upward from the centre

Hope this information will clear your doubt about
interfrence

If you have any doubt do ask on the forum, our experts will help
you out