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Question
An object is placed at a distance of 20 cm in front of a concave lens of focal length 20 cm. find: the magnification of image.
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Solution
Object distance, u = -20 cm
Focal length, f = -20 cm (concave lens)
For a lens, magnification is
m = `"v"/"u"`
`therefore "m" = (-10)/-20`
∴ m = + 0.5
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