Question

A magnified, inverted image is located a distance of 32.0 cm from a concave mirror with a focal length of 12.0 cm. Determine the object distance and tell whether the image is real or virtual.

1 / f = 1 / do + 1 / di where f = 12 cm and do = 32 cm

Answer 1

We can find the object distance from the mirror equation:

$$\dfrac{1}{d_o}+\dfrac{1}{d_i}=\dfrac{1}{f},$$ $$d_o=\dfrac{1}{\dfrac{1}{f}-\dfrac{1}{d_i}}=\dfrac{1}{\dfrac{1}{12\ cm}-\dfrac{1}{32\ cm}}=19.2\ cm.$$

The image is inverted, therefore, it is real.