Answer: True
Refraction is a phenomenon in which the light bends or changes its direction (and changes the speed of propagation, as well) when passing through a medium with a refractive index
different from the other medium.
Where the Refractive index is a number that describes how fast light propagates through a medium or material:
Being
a relation between the speed of light in vacuum
and its speed in the other medium
.
It is important to note that in this process, the wavelength may be modified because it depends on the medium, however, the refracted ray of light does not change its frequency.