Question

(1) Diffraction
(2) Doppler effect
(3) Polarisation of wave​

Answer 1

Diffraction:

Diffraction is the slight bending of light as it passes around the edge of an object.

Doppler Effect:

An increase or decrease in the frequency of sound, light, or other waves as the source and observer move towards or away from)each other. The effect causes the sudden change in pitch noticeable in a passing siren, as well as the red shift seen by astronomers.

Polarisation of Wave:

Polarized light waves are light waves in which the vibrations occur in a single plane. The process of transforming unpolarized light into polarized light is known as polarization.