Vidyarthi Academy

Home NCERT Solutions Chapter Notes Test Papers Contact Us

CBSE NOTES CLASS 12 PHYSICS

CHAPTER 10 WAVE OPTICS

Newton’s corpuscular theory

Wave theory - nature of electromagnetic waves

Wave front

Huygens principle

Refraction of a plane wave from rarer to denser medium

Refraction of a plane wave from denser to rarer medium

Reflection of a plane wave by a plane surface

Behaviour of a plane wave front with different surfaces

The Doppler effect

Superposition principle

Coherent sources of light

Interference of light

Young’s double slit experiment

Fringe width in double slit experiment

Diffraction of light

Single slit experiment

Double slit vs single slit patterns

Interference vs diffraction due to single slit

Constraints for diffraction due to single slit

Viewing the diffraction pattern

Energy is conserved during interference and diffraction

When can we consider the light beam to be parallel beam in single slit experiment?

Resolving power of an objective lens

Fresnel distance

Polarisation

Polarisation by transmission

Polarisation by scattering

Polarisation by reflection - Brewster’s law

Law of Malus

Polaroid and uses of polaroids

CBSE NOTES CLASS 12 PHYSICS

CHAPTER 10 WAVE OPTICS

Huygens principle

  1. Every point on given wave front (called primary wave front) acts as a fresh source of new disturbance called secondary wavelets.

  2. The secondary wavelets travel in all the directions with the speed of light in the medium.

  3. A surface touching these secondary wavelets tangentially in the forward direction at any instant gives the new (secondary) wave front of that instant

???

If we wish to determine the shape of the wave front at time = τ, we draw spheres of radius from each point on the spherical wave front where v represents the speed of the wave in the medium.

Common tangent to all these spheres gives the new position of the wave front at t = τ.

Huygens proposed that the amplitude of the secondary wavelets is maximum in the forward direction and zero in the backward direction. Huygens could explain the absence of the back wave using this assumption, but it is not correct. The easiest explanation is that the backward-propagating portions are destructively interfered with by the wavelets from all of the other wave fronts.

Previous
Next