Question

Write any two points of difference between interference pattern due to double-slit and diffraction pattern due to single-slit.

Hint:

Quick memory trick:

Interference → two sources, equal fringes
Diffraction → one slit, broad central maximum

Answer 1

Difference Between Double-Slit Interference and Single-Slit Diffraction
Here are two main points of difference:
1. Origin of Pattern:
- Double-Slit Interference: The pattern arises due to superposition of light waves from two coherent sources.
- Single-Slit Diffraction: The pattern arises due to interference of light waves from different parts of a single slit.
2. Nature of Fringes:
- Double-Slit Interference: The fringes are equally spaced and have nearly uniform intensity across the pattern.
- Single-Slit Diffraction: The fringes are unequally spaced and the intensity decreases for higher-order maxima.

Summary:
- Double-slit: interference of two sources, uniform bright and dark fringes.
- Single-slit: diffraction of one slit, central maximum brightest, side maxima weaker with increasing order.