1. Change in Speed: Light travels at a slower speed in denser mediums like glass compared to air. This is because the light interacts with the atoms in the glass, slowing it down.
2. Bending of the Light Ray: As the light ray enters the glass at an angle, the change in speed causes it to bend. This bending is called refraction. The direction of the bending depends on the angle of incidence and the refractive indices of the two mediums (air and glass).
3. Snell's Law: The relationship between the angle of incidence (the angle at which the light ray hits the glass surface), the angle of refraction (the angle at which the light ray bends in the glass), and the refractive indices of the two mediums is described by Snell's Law:
```
n1 * sin(θ1) = n2 * sin(θ2)
```
where:
* n1 is the refractive index of air
* n2 is the refractive index of glass
* θ1 is the angle of incidence
* θ2 is the angle of refraction
4. Total Internal Reflection: When the angle of incidence exceeds a certain critical angle, the light ray is completely reflected back into the air. This phenomenon is called total internal reflection and is responsible for the sparkle of diamonds and the operation of optical fibers.
In summary:
* Light slows down when it enters glass.
* The change in speed causes the light ray to bend, resulting in refraction.
* The angle of refraction is determined by Snell's Law.
* At a certain critical angle, the light ray undergoes total internal reflection.
Refraction is a fundamental principle in optics and has numerous applications, including lenses, prisms, and fiber optics.
