Final answer:
Reflection is the bouncing back of light, while refraction is the bending of light. Total internal reflection occurs when light is completely reflected back into a medium. Dispersion is the spreading of light into its individual colors.
Step-by-step explanation:
Reflection: The bouncing back of light when it hits a surface and cannot pass through is called reflection. It follows the law of reflection, which states that the angle of incidence is equal to the angle of reflection.
Refraction: Refraction is the bending of light as it passes from one medium to another. The speed of light changes in different mediums, causing the direction of light to change.
Refractive index: The refractive index is a measure of how much a medium can slow down light. It is the ratio of the speed of light in a vacuum to the speed of light in the medium.
Total internal reflection: Total internal reflection occurs when light traveling in a medium with a high refractive index strikes the boundary with a medium of lower refractive index at an angle greater than the critical angle. Instead of being refracted, all the light is reflected back into the first medium.
Critical angle: The critical angle is the angle of incidence that produces an angle of refraction of 90°. It is the minimum angle of incidence at which total internal reflection occurs.
Dispersion: Dispersion is the spreading of white light into its individual colors. It occurs because different colors of light have different wavelengths and different refractive indices.
Pleochroism: Pleochroism is the property of certain minerals to show different colors when viewed from different angles or under different lighting conditions.