$A$ mirror of focal length $f$ is immersed in water $(\mu = 4/3)$. The focal length of the mirror in water will be ......

What will be the height of the image when an object of height $2 \ mm$ is placed on the principal axis of a convex mirror (of radius of curvature $40 \ cm$) at a distance of $20 \ cm$ from the mirror?

Two identical objects are placed in front of a convex mirror and a concave mirror,both having a radius of curvature of $12 \ cm$,at the same distance of $18 \ cm$ from the respective mirrors. The ratio of the sizes of the images formed by the convex mirror to that formed by the concave mirror is:

The image formed by a convex mirror of a real object is larger than the object:

$A$ convex mirror of focal length $f$ forms an image which is $\frac{1}{n}$ times the size of the object. The distance of the object from the mirror is

You are asked to design a shaving mirror assuming that a person keeps it $10\,cm$ from his face and views the magnified image of the face at the closest comfortable distance of $25\,cm$. The radius of curvature of the mirror would then be.....$cm$.