Understanding Refraction
* Refraction is the bending of light as it passes from one medium to another (like air to water). This bending happens because light travels at different speeds in different mediums.
* Normal: The normal is an imaginary line perpendicular to the surface at the point where the light ray strikes.
Why No Refraction Along the Normal
* Equal Angles: When a light ray travels along the normal, the angle of incidence (the angle between the incoming light ray and the normal) is 0 degrees. Since the angle of incidence and the angle of refraction are always measured relative to the normal, the angle of refraction is also 0 degrees.
* No Change in Direction: A 0-degree angle of refraction means the light ray continues in the same direction after passing through the boundary. It doesn't bend.
In Simpler Terms:
Imagine a light ray hitting a flat surface like a window. If the ray hits the window head-on (along the normal), it goes straight through without changing direction. There's no bending because the light is traveling at the same speed in both the air and the glass.
Important Note: This applies to situations where the two mediums have a clear boundary. If the boundary is not sharp or if the medium is not homogeneous, light might still scatter or bend even if it initially travels along the normal.
