What happens when light changes direction in a glass block?

When light changes direction in a glass block, this phenomenon is known as refraction. Refraction occurs when light travels from one medium to another — in this case, from air into glass. This change in medium causes the light to slow down and bend at the boundary between the two materials. The degree of bending depends on the angle at which the light hits the glass and the optical properties of both the air and the glass.

In refraction, the light rays will change direction, and this bending of light is responsible for various optical effects, such as the way objects appear distorted when viewed through a glass of water, or the way lenses focus light to form images. This concept is foundational in understanding how prisms and lenses function in optics.

The other concepts such as reflection, diffraction, and absorption involve different interactions of light with materials. Reflection refers to light bouncing off a surface, diffraction is the bending of light around obstacles or openings, and absorption occurs when light is taken in by a material rather than transmitted or reflected. These processes do not describe the bending of light as it passes through a different medium, which is why refraction is the pertinent term in this context.