Refraction is caused by a. light bouncing off a surface. b. light changing colors as it enters a new medium. c. light speeding up as it enters a new medium. d. light slowing down as it enters a new medium.

Refraction involves the bending of light. But why does light bend? It’s because light changes its path when it enters a different medium.
Each medium has its own density and properties. When light travels from one medium to another, like from air to glass, its speed changes.
This speed change causes the light to change direction.
The amount of bending depends on the difference in densities between the two media and the angle at which light enters the new medium.
For instance, light bends more when it goes from air (less dense) into water (more dense) than when it goes from air into glass.
Understanding the path of light helps us design lenses, glasses, and even understand why a straw looks bent in a glass of water.

When light enters a new medium, its behavior changes. A medium can be anything like air, water, or glass.
This is because each medium has different optical properties which affect the speed of light.
When light moves from one medium to another, it slows down or speeds up, depending on the properties of the media involved.
The key term here is 'refractive index,' which is a measure of how much the light will bend.
When light moves from a medium with a lower refractive index to a medium with a higher refractive index, it bends towards the normal line (an imaginary line perpendicular to the surface of the medium).
Conversely, when light goes from a higher refractive index medium to a lower one, it bends away from the normal line.
This fundamental principle is crucial in optics and various real-world applications like fiber optic cables and eyeglass lenses.

The speed of light is constant in a vacuum but varies in different media.
In a vacuum, light travels at approximately 299,792 kilometers per second (km/s).
However, when light enters a medium like water or glass, it slows down.
This speed reduction causes the light to refract.
The refractive index of a medium can be calculated by the formula:
ewline ewline ewline ewline where n is the refractive index, c is the speed of light in a vacuum, and v is the speed of light in the medium.
The higher the refractive index, the slower the speed of light in that medium.
Understanding how the speed of light affects refraction helps us grasp why objects appear bent or distorted in water and how lenses can focus light.
It lays the foundation for technologies like microscopes, cameras, and even corrective eyewear.