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Two identical thin planoconvex glass len...

Two identical thin planoconvex glass lenses (refractive index `1.5)` each having radius of curvature of `20cm` are placed with their convex surfaces in contact at the centre. The intervening space is filled with oil of refractive index `1.7`. The focal length of the combination is

A

`-20cm`s

B

`-25cm`

C

`-50cm`

D

`50cm`

Text Solution

Verified by Experts

The correct Answer is:
C
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