The Nervous System, The Eye
The Optics of Vision Physical Principles of Optics Slower velocity than air. Refractive Index of a transparent substance is the ratio of its velocity in air to the velocity in the transparent object. Perpendicular - The direction light travels is always perpendicular to the wave front, When light passes through an angulated surface, it is bent (refracted) at some angle if the refractive indices of the two media are different. The angle depends on the refractive index of the barrier material and the angle between the two surfaces. Refractive Principles and their Application to Lenses A Convex Lens - Converge Light that passes the lens perimeter is refracted - bent toward the center - to make perpendicular to the wavefront. A Concave Lens - divergence Light through the lens perimeter are refracted away from the midline - bent away - to make themselves perpendicular to the wave front. Focal Length of the Lens Focal Length ...