Which phenomena support only the wave theory of light? check all that apply.

1.reflection
2.refraction
3.diffraction
4.interference
5.photoelectric effect

Diffraction and interference    

Explanation:

Light has a property that it exhibit both wave like and particle like behavior. It is an electromagnetic wave. It do not require any medium for its propagation.

Light shows diffraction and interference both. In interference of light wave, two waves combine to form an interference pattern. While in diffraction of light light bends through the obstacles.

So, the correct options are "diffraction and interference".

c)as speed changes, wavelength and frequency change.

everything changes!

because growing process had stoped after 4-5 year