Question

is it possible that a converging lens (in air) behaves as a diverging lens when surrounded by another medium? give a reason for your answer.

Answer 1

Yes, it is possible. The lens works according to the laws of refraction of light. Consider a lens which is convergent when placed in the air. Now if we place this lens in another medium whose refractive index is greater than that of the lens, the lens will act as a diverging lens.