Object height (O) = 2 cm
Focal length (f) = 12 cm (negative)
Object distance (u) = 20 cm (negative)
1\over u + 1\over v = 1\over f
โ – 1\over 20 + 1\over v = – 1\over 12
โ 1\over v = – 1\over 12 + 1\over 20
โ 1\over v = -5 + 3\over 60
โ 1\over v = – 2\over 60
โ 1\over v = – 1\over 30
โ v = – 30 cm
Hence, the image is formed at a distance of 30 cm in front of the mirror.
Image\ size\over object\ size=Image\ distance\over object\ distance
โ I\over 2=-30\over 20
โ I = {30\over 20} ร 2 = – 3 cm
Hence, the length of the image = 3 cm
The image will be real, inverted and magnified.