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

Two objects $A$ and $B$ are placed at $15\,cm$ and $25\,cm$ from the pole in front of a concave mirror having a radius of curvature $40\,cm$. The distance between the images formed by the mirror is $..........\,cm$.

$A$ square object of area $100\,cm^2$ is placed perpendicular to the principal axis of a concave mirror. If the lateral magnification of the mirror,for the above object position,is $0.4$,then the area of the image will be......$cm^2$.

As the position of an object $(u)$ reflected from a concave mirror is varied,the position of the image $(v)$ also varies. By letting the $u$ change from $0$ to $+\infty$,the graph between $v$ versus $u$ will be:

$A$ candle flame of $3 \, cm$ is placed at $300 \, cm$ from a wall. $A$ concave mirror is kept at distance $x$ from the wall in such a way that the image of the flame on the wall is $9 \, cm$. Then $x$ is......$cm$.

Consider a concave mirror of $10 \,cm$ focal length illuminated by an object kept at a distance of $25 \,cm$. The distance at which the image is formed and its magnification respectively are