If the focal length of a concave mirror be 15cm then what is its radius of curvature?

The focal lentht of a concave mirror is

Define focal length of concave mirror.

The focal leght of a spherical mirror is 40 cm. What is its radius of curvature ?

The ratio of the focal length of spherical mirror to its radius of curvature is-

A rectangular glass slab of thickness 3 cm and of refractive index 1.5 is placed in front of a concave mirror perpendicularly on its axis. The radius of curvature of the mirror is 10 cm. At what point should an object be placed on the principal axis so that its image will be formed on the object?

What will be the change in focal length f of a concave mirror when immersed in a liquid of refractive index n?

The focal length of a concave mirror is 30 cm. An object is placed at a distance of 45 cm in front of the mirror. A plane mirror is placed perpendicularly on the principal axis of the concave mirror in such a way that the object is situated in between the two mirrors. Light rays from the object at first are reflection from the concave mirror and then from the plane mirror. As a result the final image coincides with the object. What is the distance between the two mirros?

What will be the change in focal length f of a concave mirror when immerged in a liquid of refractive index n?