If $x$ is the distance of an object from the focus of a concave mirror and $y$ is the distance of the image from the focus, then which of the following graphs is correct between $x$ and $y$?

$A$ convex mirror has a focal length $f$. $A$ real object is placed at a distance $f$ in front of it from the pole. The image is produced at:

The image formed by a convex mirror of focal length $f$ is $(1/n)$ times the size of the object. The distance of the object from the mirror is:

An object of height $5 \, cm$ is placed at a distance of $1 \, m$ from a concave mirror having a radius of curvature of $20 \, cm$. The height of the image is ....... $cm$.

The focal length of a convex mirror is $20\, cm$. Its radius of curvature will be.....$cm$.

$A$ spherical mirror forms an erect image three times the linear size of the object. If the distance between the object and the image is $80 \, cm$,the focal length of the mirror is........ (in $, cm$)