If an object of $4 \, cm$ height is placed at a distance of $12 \, cm$ from a concave mirror,then its image is formed at a distance of $24 \, cm$ from the mirror and behind it. What will be the height of the image (in $, cm$)?

Which mirror is used by dentists?

Through which of the following points will a ray passing through the centre of curvature and reflected by a concave mirror pass?

$A$ beam of light is incident through the holes on side $A$ and emerges out of the holes on the other face of the box as shown in the Figure. Which of the following could be inside the box?

Identify the device used as a spherical mirror or lens in the following cases,where the image formed is virtual and erect in each case.
$(a)$ Object is placed between the device and its focus,image formed is enlarged and behind it.
$(b)$ Object is placed between the focus and the device,image formed is enlarged and on the same side as that of the object.
$(c)$ Object is placed between infinity and the device,image formed is diminished and between the focus and optical centre on the same side as that of the object.
$(d)$ Object is placed between infinity and the device,image formed is diminished and between the pole and focus,behind it.

The radius of curvature of a spherical mirror is half of the focal length.