3. What is Refraction?
• Refraction is the bending of light as it passes from one medium to another
with a different density.
• Example: Light bending when entering water from air.
4. Why Does Refraction Happen?
• Light changes speed when it moves between materials.
• Faster in air, slower in water or glass.
• This speed change causes the light to bend.
5. Laws of Refraction
• First Law: The incident ray, refracted ray, and normal all lie in the same
plane.
• Second Law (Snell's Law): n1 * sin(θ1) = n2 * sin(θ2)
6. Refractive Index
• Definition: Ratio of the speed of light in vacuum to the speed of light in
the medium.
• Formula: n = c/v
• Example values: Air ~1.00, Water ~1.33, Glass ~1.5
7. Effects of Refraction
• Bending of a stick in water
• Formation of mirages
• Lens focusing in glasses and cameras
9. Summary
• Refraction is key to many optical technologies.
• It depends on the change in speed of light.
• Refractive index determines how much bending occurs.
