Explain what is meant by diffraction of light. Describe a simple experiment to demonstrate diffraction at a single slit.

Explanation

Bending of light near the edge of an obstacle or slit and spreading into the region of geometrical shadow is known as diffraction of light.
The diffraction phenomenon is classified into two types :
1. Fraunhofer diffraction : The source of light and the screen on which the diffraction pattern is obtained are at infinite distance from the diffracting system. In this case, the wavefront due to diffraction is plance wavefront. The diffraction pattern is obtained by using a convex lens.
2. Fresnel diffraction : The source of light and the screen are kept at finite distances from the diffracting system. In this case, we obtain a cylindrical or spherical wavefront due to this diffraction.