Optical Lenses

Optical Lenses is a small, easy to use, handy application, specially designed to illustrate the function of convex and concave optical lenses. Both the size and the distance of the object and the focal length may be adjusted by the user.
In optics, refraction occurs when light waves crosses a boundary between two optical media with different refractive indexes.
At the boundary, the waves phase velocity is altered, it changes direction, and its wavelength increases or decreases but its frequency remains constant. For example, a light ray will refract as it enters and leaves glass; understanding of this concept led to the invention of lenses and the refracting telescope.
Lenses are classified by the curvature of these two surfaces. A lens is biconvex (or just convex) if both surfaces are convex, likewise, a lens with two concave surfaces is biconcave (or concave).
If one of the surfaces is flat, the lens is termed plano-convex or plano-concave depending on the curvature of the other surface. A lens with one convex and one concave side is termed convex-concave, and in this case if both curvatures are equal it is a meniscus lens.