# Wave Optics Class 12 Notes Physics Chapter 10

#### CHAPTER AT A GLANCE

1. Wavefront: The locus of all particles in a medium, vibrating in the same phase is called wavefront.

1. When the light source is point source then the wavefront is spherical.
2. When the light source is linear source then the wavefront is cylindrical.
3. When the light source is at large distance then the wavefront appears to be plane.

2. Superposition Principle: When two or more wave motions travelling through a medium superimpose one another, the resultant displacement of each particle of the medium at any instant is equal to the vector sum of the displacements produced by the two waves separately.

3. Interference: When two or more coherent waves travels in same direction, nearly in a line , they superpose and give interference.* Interference is the phenomenon of conservation of energy.For two waves of amplitudes a1 and a2

5. Diffraction of light : The phenomena of bending of light waves around the sharp edges of opaque obstacles or aperture and their encroachment in the geometrical shadow of obstacle or aperture and their encroachment in the geometrical shadow of obstacle or aperture is defined as diffraction of light. Necessary conditions of diffraction of waves : The size of the obstacle (a)
must be of the order of the wavelength of the wave (lamda).i.e. a/lamda = 1

6. Fraunhoffer diffraction at single slit : Diffraction occurs due to super position between the wavelets originated from same wave front. For diffraction, size of aperture is order of wavelength of wave.

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