A concave lens has same radii of curvature for both sides and is made of material of refractive in index `1.6` It is immersed in a liquid of `mu = 1.4` Calculate ratio of focal lengths of lens in air and liquid.

Answer

`0.238`

Explanation

Use `(1)/(f_(a)) = ((mu_(g))/(mu_(a)) - 1)((1)/(R_(1))-(1)/(R_(2)))`
and `(1)/(f_(l)) = ((mu_(g))/(mu_(l)) - 1)((1)/(R_(1)) - (1)/(R_(2)))`