Two ideal slits 
and 
are at a distance 
apart and illuminated by light of wavelength 
passing through an ideal source slit 
placed on the line through 
as shown below. The distance between the plane of slits and the source slit is 
.
A screen is held at a distance 
from the plane of the slits. The minimum value of 
for which there is darkness at 
is
Text Solution
Verified by ExpertsC
Path difference between the waves reaching at 0,
where, 
initial path difference and 
path difference between the waves after emerging from slits.
Now, 
and 
(from binomial expansion)
For obtaining dark at 
must be equals to 
.
i.e. 
or 
For minimum distance ( 
),
So, 
Prepare Smarter with CGP Edu
Get practice questions, solutions, and test series in one place.
Write a Review
Share your experience with this question and solution.
Commentary
Send your comment, doubt, correction, or feedback to admin.
Similar Questions
Explore conceptually related problems