The density. Refraction occurs at the boundary between two media of differing densities, such as air and water.
Refraction occurs when light encounters a medium with different optical density.
Refraction occurs when the wave changes velocity. The light travels at different speeds in different mediums, so for refraction to occur it is necessary for the light to pass from one medium to another at an angle different than 0 and 90 degrees.
It is because of the change in velocity of light in two different media.
No refraction can occur either way!
Refraction is the bending of the rays of light when it travels from one medium to another... For refraction to occur there should be some difference in the refractive index of the materials.... Refraction can also occur in Opaque medium........
Refraction occurs at the point where light passes from one transparent medium to another medium of a different density. (see more at the related link)
For refraction to occur, there must obviously be two different substances that are both transparent to the radiation or waves under consideration. Also, the two substances must have different indices of refraction.
For refraction to occur in a wave, the wave must enter a new medium at an angle.
Dispersion will occur, in the sense that the phase velocity of the different wavelengths will be different. What you may be asking is whether refraction (a change in the direction of the light) will occur. Refraction will only be visible if the light impacts at an oblique angle, not 90 degrees.
refraction occurs when a light ray passes from a rarer to denser medium or vice versa