Question

Monochromatic coherent light passing through two thin slits is viewed on a distant screen. Are the bright fringes equally spaced on the screen? If so, why? If not, which ones are closest to being equally spaced?

Short answer

No, the bright fringes are not equally spaced on the screen

Step-by-step solution

Define the principle of superposition.

The principle of superposition states:

When two or more waves overlap, the resultant displacement at any point and at any instant is found by adding the instantaneous displacements that would be produced at the point by the individual waves if each were present alone.

Determine whether the bright fringes are equally spaced on the screen.

The bright fringes are not equally spaced on the screen because if the angle of the diffraction changes, the distance between the adjacent fringes on the screen also changes.

Hence, the bright fringes equally are not spaced on the screen.