$A$ diminished virtual image can be formed only in

An object $2.5 \, cm$ high is placed at a distance of $10 \, cm$ from a concave mirror of radius of curvature $30 \, cm$. The size of the image is ........ $cm$.

$A$ concave mirror of focal length $f$ forms an image $n$ times the size of the object. If the image is real, then the distance of the object from the mirror is .......

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

$A$ convex lens (of focal length $20\, cm$) and a concave mirror,having their principal axes along the same lines,are kept $80\, cm$ apart from each other. The concave mirror is to the right of the convex lens. When an object is kept at a distance of $30\, cm$ to the left of the convex lens,its image remains at the same position even if the concave mirror is removed. The maximum distance of the object for which this concave mirror,by itself,would produce a virtual image would 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........$cm$.