Question

1) A two slit interference/diffraction pattern is set up (thus for this problem we will take into account the effects of both diffraction and interference). You are given that the screen is 1.8 m away from the slits with width .01 mm and spacing .05 mm and light of wavelength 640 nm is used. What is the smallest order interference maximum that is \"missing\" from the interference/diffraction pattern on the screen? n=

Answer 1

Sol:

Given data:
i) wavelength

ii) distance of screen

iii) slit width

iv) slit spacing

Now position of nth order interference maximum is given as-

And position of mth order differaction minimum is given as-

Hence

Now suppose nth order interference maximum is missing.

Means first order differaction minimum is overlapping on nth order interference maximum

Hence

or

Hence 5th order interference maximum is missing.