An object is placed at a distance of $12 \mathrm{cm}$ from a concave mirror. The image formed is real and four times larger than the object. Calculate the distance of the image from the mirror.

When a concave mirror is placed facing the sun, the sun's rays converge to a point $10 \mathrm{cm}$ from the mirror. Now, an erect, $2 \mathrm{cm}$-long pin is placed $15 \mathrm{cm}$ away on the principal axis of the mirror. If you want to get the image of the pin on a card, where would you place the card? What would be the nature and height of the image?