The direction of a ray of light incident on a concave mirror is shown by $PQ$,while the directions in which the ray would travel after reflection are shown by four rays marked $1, 2, 3,$ and $4$. Which of the four rays correctly shows the direction of the reflected ray?

An object is placed in front of a concave mirror of focal length $f$. $A$ virtual image is formed with a magnification of $2$. To obtain a real image of the same magnification,the object has to be moved by a distance of:

The distance between an object and its image (magnified by $-\frac{1}{3}$) is $30 \ cm$. The focal length of the mirror used is $\left(\frac{x}{4}\right) \ cm$,where the magnitude of the value of $x$ is . . . . . . .

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:

$A$ square wire frame of side $3 \, cm$ is placed at a distance of $25 \, cm$ from a concave mirror of focal length $10 \, cm$. The area of the image is ........ $cm^2$.

Distance between an object and its three times magnified real image is $40 \ cm$. The focal length of the mirror used is . . . . . . $cm$.