Overview Physics Gravitation Physics Class 11th

The same size images are formed by a convex lens by a convex lens when the object is placed at 20cm or at 10cm from the lens. The focal length of convex lens is ……………cm.

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1 Answer

Answered by

Vishal Baghel | Contributor-Level 10

a month ago

Image is virtual, when an object is placed at distance 10 cm from the lens and image is real when object is placed at 20 cm from the lens.

Thus, m₁ = -m₂ => $\frac{f}{f - 10} = \frac{- f}{f - 20} \Rightarrow f = 15 c m$

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