Theory of Light:

Newton proposed 'Corpuscular Theory of Light'.

2. According to corpuscular theory, light consists of a stream of tiny, light and perfectly elastic particles called 'corpuscles'.

3. The velocity of light is different in different media. 

4. According to the corpuscular theory of light, various colours of light are supposed to be due to different sizes of corpuscles.

5. Corpuscular theory could not explain the phenomena of interference, diffraction and polarization of light.

6. According to Huygens' theory, light travels in the form of waves. 

7. The basis of Huygens' wave theory of light is his principle concerning construction of wavefront.

8. The imaginary three dimensional surface formed by the particles of a medium which are vibrating in the same phase is called a 'wavefront'.