﻿ Diameter of a plano-convex lens is 6 cm and thickness at the centre is 3 mm. If the speed of light in the material of the lens is , the focal length of the lens is:   : Kaysons Education

# Diameter Of A Plano-convex Lens Is 6 Cm And Thickness At The Centre Is 3 Mm. If The Speed Of Light In The Material Of The Lens Is , The Focal Length Of The Lens Is:

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## Question

### Solution

Correct option is

30 cm

As the lens is plano-convex, i.e., R1 = R and R2 = ∞,

As speed of light in the medium of lens is

From figure,

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