Optical Board - Ray Diagram - Concave Mirror

Purpose

To locate the image of a concave mirror by using the three principal rays.

Equipment

Optical board with parabolic concave mirror, half-silvered and full-silvered mirrors on mount, convex lens.

Images

l3-12

Description

This is a short focal length concave parabolic mirror which produces a small image close to the mirror for the setup photographed. The central ray passes through a half-silvered mirror which deflects half of the light to the tip of the object arrow. The upper mirror can be rotated to create any of the three principal rays. Keep the mirror reasonably close to the mirror to produce a larger image. The convex lens keeps the light ray narrow. ◙◙The object can be moved within the focal point of the mirror to produce an anlarged virtual image behind the mirror.

References

Samuel Derman, Ray Tracing with Spherical and Parabolic Reflectors, TPT 28, 590-593 (1990).