Question

as light travels from a rarer to a denser medium it will have​

Answer 1

Answer:

Hence, in a medium of greater optical density (optically denser), light will travel slower than in a medium of lower optical density (optically rarer). Therefore, when light travels from a rarer to a denser medium, its speed decreases. 

Answer 2

When light travels from an optically rarer medium to an optically denser medium, the speed decreases because of the change in wavelength.

Explanation:

• According to the law of refraction of light, when a ray of light passes from a rarer medium to a denser medium, it bends towards the normal.
• The energy of the wave depends only on its frequency.
• Since the frequency does not change as the wave travels from one medium to another, therefore, the energy of the waves remains same and does not decrease.
• Speed of light is more in the rarer medium than in a denser medium, when light travels from rarer to denser medium-light tends to move towards normal.