The image of an object formed by a lens is real, inverted and of the same size as the object. If the image is at a distance of 40 cm from the lens, what is the nature and power of the lens? Draw ray diagram to justify your answer.
Object distance = 40 cm
Image: real, inverted and same size as object.
Real and inverted image is formed by the convex lens only. For image to be of same size as object, object must be placed at 2f distance from pole.
Since, object distance = 40 cm
2f = 40 cm
f = 20 cm
Power of lens = 5 D
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