Which letters represent constructive interference in this diffraction pattern? check all that apply.

A, C and D

Explanation:

Interference occurs when two waves superimpose to form a wave having a smaller or larger amplitude.

Constructive interference is said to occur when two waves superimpose to produce a wave having larger amplitude. It occurs for the waves having phase difference of multiple of 2π. On the other hand, destructive interference occurs for the waves having phase difference  π, 3π, ..and so on.

In the given picture, the bright regions represent constructive interference where as the dark ones between them represent destructive interference. Thus, the correct letters representing constructive interference are: A, C and D.

the answer for apex is the lowest