An object is placed in front of a spherical mirror, and a $2$ times magnified image is formed on a screen. Choose the $\text{CORRECT}$ option.

The separation between the screen and a concave mirror is $2r$. An isotropic point source of light is placed exactly midway between the mirror and the screen. The mirror has a radius of curvature $r$ and reflects $100\%$ of the incident light. Find the ratio of illuminances on the screen with and without the mirror.

Define the focal plane of a concave mirror.

If the coordinates of the position of an object are $(-60 \, cm, 6 \, cm)$,then the coordinates of the image will be:

Two identical objects are placed in front of a convex mirror and a concave mirror,both having a radius of curvature of $12 \ cm$,at the same distance of $18 \ cm$ from the respective mirrors. The ratio of the sizes of the images formed by the convex mirror to that formed by the concave mirror is:

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: