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

$A$ diminished virtual image can be formed only in

$A$ concave mirror produces an image of an object such that the distance between the object and the image is $20\ cm$. If the magnification of the image is $-3$,then the magnitude of the radius of curvature of the mirror is: (in $cm$)

$A$ concave mirror gives an image three times as large as the object placed at a distance of $20 \ cm$ from it. For the image to be real,the focal length should be ...... $cm$.

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

$A$ 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).