A hollow double concave lens is made of very thin transparent material. It can be filled with air or either of two liquid `L_(1)` and `L_(2)` having refractive indices `mu_(1)` and `mu_(2)` respectively `(mu_(2)gtmu_(1)gt1)`. The lens will diverge a parallel beam of light if it is filled with

Options

A. air and placed in air
B. air and immersed in `L_(1)`
C. `L_(1)` and immersed in `L_(2)`
D. `L_(2)` and immersed in `L_(1)`

Answer

d.

Explanation

We know that `(1)/(f)=((mu_(2))/(mu_(1))-1)((1)/(R_(1))-(1)/(R_(2)))`
For divergence, `mu_(2)gtmu_(1)`
Here, `((1)/(R_(1))-(1)/(R_(2)))` is negative.
Therefore, (d) is the correct option.