In deriving the single slit diffraction pattern, it was stated that the intensity is zero at angle `n lambda//a`. Justify this by suitable dividing the slit to bring out the cancellation.

Explanation

Consider that a single slits of width s is divided into n amaller slits .
` therefore ` Width of each slit , `d'=(d)/(n)`
angle fo diffraction is given by the relation ,
`theta=(d/dlambda)/(d)=(lambda)/(d)`
Now ,each fo these infinitesimally small slit sends zero intensity in direction `theta` Hence , the combination of therse of these slits will give zero intensity .