A concave mirror and a convex lens are held in water

cbse
refractionoflight

#1

A concave mirror and a convex lens are held in water. What changes, if any do you expect in their focal length?


#2

The focal length of a concave mirror independent of the medium and a convex lens depends on medium when they placed in water.
The focal length of the mirror - Does not change.
The focal length of the convex lens - Changes (means increases 4 times).