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A diverging lens is made of material wit...

A diverging lens is made of material with refractive index `1.3` and has identical concaves surfaces of radius `20 cm.` The lens is immersed in a transparent medium with refractive index `1.8.`
(a) What is now the focal length of the lens?
(b) What is the minimum distance taht an immersed object must be from the lens so that a real image is formed?

Text Solution

Verified by Experts

The correct Answer is:
A, B, C
(a) `1/f=(1.3/1.8-1)(1/(-20)-1/(+20))`
`:. f=+36 cm`
(b) Between O and `F_1` image is virtual. Hence, for
real image.
`|mu|ltf` or `36 cm`
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