Ray Diagrams for Mirrors - Page 1 - Physics 2 - University of Florida - Prof. Selman Hershfield

• Remember that light is coming from the object in all directions and from all points on the object. The principle rays are particular rays which allow us to easily determine the location, orientation, and size of the image.
• A spherical concave (convex) mirror only approximately focuses the light to (away from) a single point - the focal point. To precisely focus the light to a point would require that the mirror be parabolic rather than spherical. Parabolic and spherical mirrors are almost the same near the vertex.
• To correct for the fact that spherical mirrors are not perfect, we will be drawing our rays reflected from the dashed line behind the mirror. This is not what happens in reality, but it will allow us to have the priniciple rays intersect at the image.
• The three principle rays go out through the focal point, in through the focal point, and through the vertex.
• The sign conventions are:
• object distance = do positive if on side of incoming light (in front of mirror)
• image distance = di positive if on side of outgoing light (in front of mirror)
• focal length = f positive for concave mirror (negative for convex mirror)
• magnification = m positive if object and image in same direction
• Equations for mirrors:

For each of the figures below draw the ray diagrams and check your results for the image location, size, and orientation using the equations.