Question

Two similar thin equi-convex lenses, of focal length f each, are kept coaxially in contact with each other such that the focal length of the combination is . When the space between the two lenses is filled with glycerine (which has the same refractive index () as that of glass) then the equivalent focal length is . The ratio will be :

A
B
C
D
Medium
NEET
Updated on : 2022-09-05
Solution
Verified by Toppr
Correct option is B)

Equivalent focal length in air,When glycerin is filled inside, glycerin lens behaves like a diverging lens of focal length (-f)

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