Task: Class Definition Understanding (ontology: Earth_Environment/SWEET)

Which of the following definitions best describes 'refraction'?

A. A fault along which strike-slip deformation is accompanied by a component of extension transverse to the fault.
B. In a broad sense, the process by which matter is excited to radiate by an external source of electromagnetic radiation, as distinguished from emission of radiation by matter, which occurs even in the absence of such a source.
C. A change of direction and possibly amplitude of an electromagnetic, acoustic, or any other wave propagating in a material medium, homogeneous on the scale of the wavelength, as a consequence of spatial variation in the properties of the medium.
D. The process in which incident radiant energy is retained by a substance.

Answer: A change of direction and possibly amplitude of an electromagnetic, acoustic, or any other wave propagating in a material medium, homogeneous on the scale of the wavelength, as a consequence of spatial variation in the properties of the medium.