Question
Wed February 15, 2012 By: Manas Khare
Give reason for following:

# Give reason for following: 1.why a convex lens behaves like a concave lens in water , if the Refractive index of lens is more than air but less than water.What will be the situation if the Refractive index of lens becomes more than water? 2.Why does an air bubble inside water behaves like a diverging lens?explain in detail.

Thu February 16, 2012
Actually the focal length of  lens depends not only on the material of lens but on the medium in which it is placed.

The focal length of the lens ( By lens maker forumla)=

n2--RI of lens,  n1--RI of medium in which is placed. So depending on the medium in which it is placed it behaves like converging , diverging.

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