Wave Optics

A light wave of frequency $$5 \times 10^{14}\ Hz$$ enters a medium of refractive index $$1.5.$$ In the medium, the velocity of the light wave is .......... and is wavelength is ..........
Wave property of electrons implies that they will show diffracion effects. Davisson and Germer demonstrated this by diffracting electrons from crystals. The law governing the diffracion from a crystal is obtained by requiring that electron waves reflected from the planes of atoms in a crystal interfere constructively (see in figure)
When two light waves of same intensity interfere, find the resultant intensity of the waves.
What happens to electric field component when unpolarized light is incident on surface such that reflacted and refracted light are at right angles?
When waves of same idensity from two coherent sources reach a point with zero path different the resulting intensity is K . When the above path difference is $$\lambda /4$$ the intensity becomes