A single-slit diffraction pattern is formed on a distant screen. If the width of the single slit through which light passes is reduced, what happens to the width of the central bright fringe? Assume the angles involved remain small.

Question

The central bright fringe becomes wider.
The central bright fringe becomes narrower.
The central bright fringe remains the same size.

Answer 1

sin T = l / a

Does this tell you anything about the angle of the central fringe, vs the width a? When a is large, T is smaller.