If the focal length of a double convex lens for red light is `f_(R)` its focal length for the violet light is

The focal length of a convex lens is

A double convex lens is immersed in water . Its focal length

Is the focal length of a lens the same for lights of all colors ?

How does the focal length of a convex lens change if monochromatic red light is used instead of monochromatic blue light?

If a convex lens is immersed in water, then its focal length