Mirror Formula and Magnification
Sign convention for ray diagram
Distances measured towards positive x and y axes (coordinate system) are positive and towards negative x and y-axes are negative. Keep in mind the origin is the pole (P). Usually, the height of the object is taken as positive as it is above the principal axis and height of the image is taken as negative as it is below the principal axis.
Mirror formula and Magnification
- 1/v + 1/u = 1/f where ‘u’ is object distance, ‘v’ is the image distance and ‘f’ is the focal length of spherical mirror, which is found by similarity of triangles.
- The magnification produced by a spherical mirror is the ratio of the height of the image to the height of the object. It is usually represented as ‘m’.
Position and Size of image formed
Size of image can be found using the magnification formula m = h’/h = – (v/u) If m is -ve it is a real image and if it is +ve it is a virtual image.
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