When an object of height 1 cm is kept at a distance of 4 cm from a concave mirror, its upright image of height 1.5 cm is formed at a distance of 6 cm behind the mirror. Calculate the focal length of the mirror(only magnitude)
u = - 4 cm
v = 6 cm
Mirror formula 1f = 1v + 1u
1f = 1−4 + 16
f = -12 cm
Focal length of the mirror is 12 cm.