Young's double slit experiment is carried out using microwaves of
wavelength `lambda=3cm`. Distance between the slits is `d= 5cm` and the distance
between the plane of slits and the screen is `D=100cm`.
(a) Find total number of maxima and
(b) their positions on the screen.

Explanation

(a) Since `d sin theta = n lamda rArr sin theta = (n lamda)/(d) lt= 1`
`therefore n lt= d/lamda = 5/3 = 1.6`
maximum number of maxima are (2 [n]+1)= 3. Thus, in this case we can have only three maximas, one central maxima and two on its either side.

(b) The position of nth maxima `y = (n lamda D)/(d)` for n = 1
`y = (lamda D)/(d) = (3 xx 100)/(5) = 60cm`
Thus, the three maximas will be at y = 0 and y = `pm60cm`