An object 18 cm in front of the concave mirror of focal length 12 cm in the figure forms a real image.

Explanation

1. 01

   Mirror formula: 1/v + 1/u = 1/f, with u = −18 cm and f = −12 cm.

2. 02

   1/v = −1/12 + 1/18 = −3/36 + 2/36 = −1/36, so v = −36 cm (36 cm in front of the mirror).

3. 03

   Magnification m = −v/u = −(−36)/(−18) = −2: the image is inverted and 2 times as tall.