Diffraction
The phenomenon of bending of light around the edges of the obstacles and its
encroachment in the region of geometrical shadow is called as diffraction.
Conditions for diffraction
➢ When a small obstacle or an aperture is placed in the path of light, some light is found in
the geometric shadow.
➢ If the width of the slit is not very large as compared to the wavelength of light used, then
the intensity in the illuminated region is not uniform.
➢ Light does not propagate strictly in a straight line, when it passes close to the edges of
objects, and the patterns produced depend on the shape and size of the object.
Types of diffraction
Fresnel Diffraction
The diffraction pattern obtained on the screen, by keeping both source and screen at finite
distances from the diffraction slit is called as Fresnel diffraction.
The phenomenon of bending of light around the edges of the obstacles and its
encroachment in the region of geometrical shadow is called as diffraction.
Conditions for diffraction
➢ When a small obstacle or an aperture is placed in the path of light, some light is found in
the geometric shadow.
➢ If the width of the slit is not very large as compared to the wavelength of light used, then
the intensity in the illuminated region is not uniform.
➢ Light does not propagate strictly in a straight line, when it passes close to the edges of
objects, and the patterns produced depend on the shape and size of the object.
Types of diffraction
Fresnel Diffraction
The diffraction pattern obtained on the screen, by keeping both source and screen at finite
distances from the diffraction slit is called as Fresnel diffraction.
