Which ray diagram demonstrates the phenomenon of refraction?
The Correct Answer and Explanation is:
The correct answer is the middle diagram.
Refraction is a fundamental phenomenon in optics defined as the bending of a light wave when it passes from one transparent medium into another. This change in direction occurs because the speed of light is different in different materials. When light crosses the boundary between two media with different optical densities, such as from air to water or from air to glass, its speed changes, causing its path to bend.
The middle ray diagram accurately illustrates this principle. It shows a single incident ray of light traveling through one medium and striking the boundary, represented by the vertical line. The ray then passes through the boundary into the second medium, but its direction is clearly altered. The transmitted ray continues on a new, bent path. This change in direction as the light ray crosses the interface is the essential characteristic of refraction. A classic real world example of refraction is a straw in a glass of water appearing bent at the point where it enters the water. The light from the submerged portion of the straw travels from water to air, bending as it reaches the observer’s eye, which creates the visual distortion.
The other two diagrams represent different optical phenomena. The diagram on the right demonstrates reflection. In reflection, a light ray strikes a surface and bounces off, remaining in the original medium instead of passing through. This is what happens when light hits a mirror. The diagram on the left illustrates scattering or dispersion. Here, a single incident ray interacts with the boundary and is redirected into multiple rays traveling in various directions. This is different from the predictable, singular bend seen in refraction. Scattering occurs when light interacts with a rough surface or small particles.
Therefore, only the middle diagram correctly portrays a single light ray bending as it passes from one medium to another, which is the definition of refraction.
