Wave Optics

Violet

Violet light has the shortest wavelength and highest refractive index in glass, so it bends the most.

Scattering of light

Shorter wavelengths like blue are scattered more by air molecules, making the sky appear blue.

2nπ radians

Constructive interference occurs when the phase difference is an even multiple of π, i.e., 2nπ.

Use of monochromatic light

Monochromatic light is not essential for diffraction; it can occur with white light too, though patterns may blur.