Physics Form 4: Chapter 5 - Concave Mirror Ray Diagrams

 

Ray diagrams are constructed by taking the path of three distinct rays from a point on the object:

X) a ray parallel to the principal axis reflected through F (the principal focus)

Y) a ray passing through C which is then reflected back along its original path
Z) a ray passing through F, which is then reflected parallel to the principal axis

Click on the diagram below to play!

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Object's position (S), focal point (F)	Image	Diagram
S < F (Object between focal point and mirror)	Virtual Upright Magnified (larger)
S = F (Object at focal point)	Reflected rays are parallel and never meet, so no image is formed. In the limit where S approaches F, the image distance approaches infinity, and the image can be either real or virtual and either upright or inverted depending on whether S approaches F from above or below.
F < S < 2F (Object between focus and centre of curvature)	Real Inverted (vertically) Magnified (larger)
S = 2F (Object at centre of curvature)	Real Inverted (vertically) Same size Image formed at centre of curvature
S > 2F (Object beyond centre of curvature)	Real Inverted (vertically) Reduced (diminished/smaller) As the distance of the object increases, the image asymptotically approaches the focal point In the limit where S approaches infinity, the image size approaches zero as the image approaches F

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