Question

The diagram shows light passing through an opening and forming bands.

There is an incident beam of light toward an opening in a grating. The light breaks into 7 different paths labeled n = 3, n = 2, n = 1, n = 0, n = 1, n = 2 and n = 3.
Which two order bands are the dimmest?

n = 0 and n = 1
n = 0 and n = 3
n = 1 and n = 2
n = 2 and n = 3

Answer 1

n = 2 and n = 3

Explanation: diffraction order intensity falls off as |n| increases, so the outer orders (n=3 and the next outer n=2) are the dimmest.