Respuesta :
Explanation :
Light shows many different types of phenomena like the reflection of light, refraction of light etc.
Refraction of light is the phenomena of bending of light when it passes from one medium to another. This is due to the difference in the refractive indices of two media.
Refractive index is given by :
[tex]n=\dfrac{c}{v}[/tex]
c is the speed of light in vacuum
v is the speed of the light in a medium.
So, refraction occurs when a wave changes its speed.
Hence, the correct option is (D) "speed".
