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?

If the lateral magnification is $-2$ for a virtual object in a spherical mirror,then:

$A$ concave mirror is used to form an image of the Sun on a white screen. If the lower half of the mirror were covered with an opaque card,the effect on the image on the screen would be

$A$ point object is placed at a distance of $30 \, cm$ from a convex mirror of focal length $30 \, cm$. Where will the image be formed?

How is it convenient to obtain an image by reflection from a spherical mirror?

$A$ 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.....$cm$.