In a double slit Fraunhofer diffraction pattern, the intensity distribution at a point on the screen is given as
I=I_(0)(sin^(2)\beta )/(\beta ^(2))cos^(2)\gamma
where
\beta
is given as
\beta =(\pi bsin\theta )/(\lambda )
and
\gamma
is given as
\gamma =(\pi (b+d)sin\theta )/(\lambda )
. Here, '
b
' is the width of each slit and '
d
' is the separation distance between the two slits and
\theta
is the angle that each ray of diffracted light makes with the normal to the grating. a) Explain the terms in the intensity relation given above. Find the positions of various maximas and minimas. Draw the intensity distribution curve from it for
d=2b
. b) Explain how the intensity pattern will get affected if we increase the slit widths keeping the separation distance between them to be the same.
(5+2)