Magnification Formula
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Description:
Whenever we observe an image of an object after reflection by spherical mirror, there can be a change in the size of object i.e. image formed can have a larger size or smaller size than the actual size of the object. This phenomenon of change in the image size is known as magnification.
Magnification is given by −
Magnification =
Size of imageSize of Object
i.e.
m =
IO
From figure −
m =
𝑨′𝑩′ -AB
Negative sign indicates that the image is inverted.
We know that, angle of incidence = angle of reflection
∠i = ∠r
Now, considering two similar triangles &9651;ABP and &9651;𝑨′𝑩′𝑷
𝑨′𝑩′AB
=𝑩′P BP
∴ -m =
-v-u
∴ m = -
vu
Where,
m = magnification.
v = Image distance.
u = Object distance.
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