State the condition for constructive interference in terms of path difference between the two waves.

Options

A. `(2n+1)lamda`
B. `2n pi `
C. `n lamda`
D. `(2n+1)(lamda)/2`

Answer

C

Explanation

For constructive interference
path difference `=n lamda` where n=0,1,2,3,…………………
n=0 is the central brigh fringe n=1 is the first bright fringe and so on.