The focal length of a spherical mirror is .......

An object is placed $40\;cm$ from a concave mirror of focal length $20\;cm.$ The image formed is

In the case of spherical mirrors,the images formed on the side of the object and images formed on the opposite side are respectively

$A$ person sees his virtual image by holding a mirror very close to the face. When he moves the mirror away from his face,the image becomes inverted. What type of mirror is he using?

In the figure shown,the image of a real object $O$ is formed at point $I$. $AB$ is the principal axis of the mirror. The mirror must be:

$A$ square wire frame of side $3 \ cm$ is placed $25 \ cm$ away from a concave mirror of focal length $10 \ cm$. What is the area enclosed by the image of the wire? (The centre of the square wire is on the axis of the mirror and the plane is perpendicular to the principal axis).