Physics - Geometrical Optics Question with Solution | TestHub

A concave mirror forms an image of the sun at a distance of 12 cm.

So, the focal length of the mirror is 12 cm.

The radius of the mirror is $\mathrm{f}\times 2=24\mathrm{cm}$.

For obtaining a virtual image that is magnified and erect, we need to place the object within the focal length.

So, the mirror must be kept at a reasonable distance of $8-10\mathrm{cm}$, which is within the focus and pole, as the radius is 24 cm. The object placed at the center forms an image at the same place.