REFRACTION OF LIGHT AND LENSES

• Refraction is when light travels from one transparent medium to another with a different optical density at an angle with the normal line to the boundary, it bends and changes direction.
• The refraction was first studied by Rene Descartes and Willebrord Snell.
• Optical Density is the degree to which a refractive material or medium slows down transmitted rays of light. The higher the optical density, the slower light travels through the material.
• The measure of an object’s optical density is called refractive index.
• Snell's law of refraction states that when the incident ray forms an angle with the normal line, the refracted ray also forms an angle with the normal line.
• Total Internal Reflection occurs when the incident ray is reflected instead. No light travels through the second medium
• Critical Angle is the highest angle of incidence where light is still refracted. Any incident angle greater than the critical angle will result in the reflection of light, instead of refraction.
• Lenses are transparent optical devices that refract light. The direction of a light ray changes when it is refracted.
• Convex Lens are lens that has a surface that bulges outward.
• Concave Lens are lens that has a surface that bulges inward.
• The interface is the point where the medium changes.