Question

Focal length of a convex lens in air is 25 cm. If it is immersed in water, then calculate the

focal length of the lens. (nw
=
4
3
, ng
=
3
2
)

Answer 1

Answer:the focal length of the convex lens in water is 33.33 cm.

Explanation:The formula for the change in focal length of a lens when it is immersed in a medium with a different refractive index is given by:

f' = f * (n2 / n1), where f is the focal length in air, n1 is the refractive index of air, and n2 is the refractive index of the new medium.

Given that n1 = 1 (refractive index of air) and n2 = 4/3 (refractive index of water),

f' = 25 * (4/3 / 1) = 25 * (4/3) = 33.33 cm

So, the focal length of the convex lens in water is 33.33 cm.