What is the path difference of destructive interference

Options

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

Answer

D

Explanation

If the waves interfere destructively, then path difference is given by ` ( lambda )/(2), (3 lambda )/(2) , (5 lambda )/(2)` etc.
Therefore path difference of a destructive interference is ` ((2n+1)lambda)/(2) ` ( where n=1,2,3,.....) etc .