^Position of maxima

Also it is found that at P for n^th maxima

In a similar way the angular position of nth bright fringe is

i.e. angular positions of 1^st, 2^nd, 3^rd maxima are

From above relation we can say that each secondary maxima occupies an angular width of , thus linear width of each secondary maxima is . As the central maxima is a spread between the angular positions to , thus its angular width is i.e. central maxima is twice wider than secondary maxima. Linear width of central maxi. is