﻿ The equi-convex lens, shown in the figure, has a focal length f. What will be the focal length of each half if the lens it cut along AB? (See fig.)                                                                     : Kaysons Education

# The Equi-convex Lens, Shown In The Figure, Has A Focal Length f. What Will Be The Focal Length Of Each Half If The Lens It Cut Along AB? (See Fig.)

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## Question

### Solution

Correct option is

2f

For equi-convex lens R1 = –R2, so that

If the lens is cut along AB, we have two plano convex lenses. For a plano convex lens, R2 = ∞. Therefore, its focal length f’ is

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