Return to main page. An Introduction to Concave Mirrors

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Object within the Mirror Curvature

Object outside mirror curvature. What happens when the object is inside of the curvature of a spherical concave mirror as shown? The procedure here will follow the two Light Ray Diagram rules that we have successfully employed previously.

Ray Diagram Rules

1) Draw two light rays.
2) Choose the easiest two!
Ray from object top to mirror and optic axis intersection. To draw the first light ray, start at the top of the object. Draw a straight line to middle of the mirror. Sketch the outgoing ray using the principle that the incident reflection angles are equal.
Ray from object top through center of curvature. The second ray passes through the center of curvature. Begin at the top of the object and draw through the center of curvature extending the line to the mirror surface.

Since the light ray is square with the mirror, the outgoing path traces over the incoming path and on past the object. This light ray is shown in red.
Real, inverted, and enlarged real image. The top of the image is located where the light rays meet. This image is inverted and enlarged. Note that this is a real image as real light rays focus to form the image.*

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* If the object gets so close to the mirror that the image appears upright, the image is no longer real but virtual.
See the Original Mirage®.
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