Question

How many interference maxima will be contained in the central diffraction maximum in the interference-diffraction pattern of two slits if the separation of the slits is exactly 13 times their width?
m = ______

How many will there be if the slit separation is an integral multiple of the slit width (that is, d = na for any value of n)? (Use the following as necessary: n.)
N = _____

Answer 1

a)

Condition for diffraction minima, for first order,     

Condition for interference maxima,   

from above two relations,

( since seperation of slits )

That is there are 13 interference maxima above the central maxima and 13 interference maxima below the central maxima.

The 13 th interference maxima coincides with the first diffraction minima. So it is not visible. Son only 12 interferce maxima are visible above the central maxima and 12 interference maxima are visible below the central maxima.

Total number of interference maxima contained in the central diffraction maximum are

( for integral value of )

b)

For