The magnification equation is a relation between image distance and object distance.

An object of size $7.0\, cm$ is placed at $27\, cm$ in front of a concave mirror of focal length $18\, cm$. At what distance from the mirror should a screen be placed,so that a sharp focussed image can be obtained? Find the size and the nature of the image.

What does negative magnification mean in the context of spherical mirrors?

If the magnification of a body of size $1\, m$ is $2$,what is the size of the image (in $m$)?

The mirror formula is the same,irrespective of whether the mirror is a convex mirror or a concave mirror.

$A$ $4.5 \, cm$ needle is placed $12 \, cm$ away from a convex mirror of focal length $15 \, cm$. Give the location of the image and the magnification. Describe what happens to the image as the needle is moved farther from the mirror.