Final answer:
When a convex lens is immersed in a liquid with a higher refractive index, the light passing through the lens slows down and turns away from the normal, bending more at the boundaries. This change in nature affects the focal length of the lens.
Step-by-step explanation:
When a convex lens is immersed in a liquid with a refractive index higher than that of the lens material, the nature of the lens changes. The light passing through the lens slows down and turns away from the normal, bending more at the boundaries between the lens and the liquid.
This change in nature affects the focal length of the lens. The focal length of a convex lens is dependent on the refractive index of the surrounding medium. Therefore, when the lens is immersed in a liquid with a higher refractive index, the focal length will change.
For example, when a convex lens made of glass is immersed in water, which has a higher refractive index than that of the glass, the focal length of the lens will decrease.