A biconcave lens made of a transparent material of refractive index 1.25 is immersed in water of refractive index 1.33. Will the lens behave as a converging or a diverging lens? Give reason.

Explanation

`(1)/(f)=((mu_(i))/(mu_(s))-1) [(1)/(R_(1))-(1)/(R_(2))]`
For concave lens `[(1)/(R_(1))-(1)/(R_(2))]=-ve`
here `=1.25`
`s=1.32`
Then `((mu_(i))/(mu_(s))-1)=-ve`
Then `(1)/(f)rarr(-ve)(-ve)`
Thus it will behave like converging lens.