The interfering fringes forward by a thin oil film on water are seen in yellow light of sodium lamp. We find the fringes

On a hot summer night, the refractive index of air is the smallest near the ground and increases with a height from the ground. When a light beam is directed horizontally, the Huygens' principle leads us to conclude that as it travels, the light beam,

Spherical wavefronts shown in figure, strike a plane mirror. Reflected wavefronts will be as shown in

The figure shows a surface XY separating two transparent media, medium-I and medium-II. The lines ab and cd represents wave fronts of a light wave travelling in medium-I and incident on XY. The lines ef and gh represent wave fronts of light wave in medium-II after refraction the Speed of light is