In deriving the single slit diffraction pattern, it was stated that the intensity is zero at angles of `(nlamda)/a`. Justify this by suitably dividing the slit to bring out the cancellation.

Explanation

Divide the single slit in to n smaller slits of width `a.=a/n`. The angle `theta=(n lamda)/a=(lamda)/(a.)`. Each of the smaller slits sends zero intensity in the direction `theta`. The combination gives zero intensity as well.