$A$ virtual image larger than the object can be obtained by

An object is placed at the principal focus of a convex mirror. The image will be at

The focal length of a concave mirror is $50 \ cm$. At what distance (in $cm$) should an object be placed to obtain a real and inverted image of double the size?

An object is at a distance $x_1$ from the focus of a concave mirror,and its image is formed at a distance $x_2$ from the focus. The focal length of the mirror is:

The distance of a real object from the focus of a convex mirror of radius of curvature $a$ is $b$. Then the distance of the image from the focus is

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: