If the image formed by a convex mirror of focal length 30 cm is a quarter of the size of the object, then the distance of the object from the mirror will be
Options
(a) 30 cm
(b) 60 cm
(c) 90 cm
(d) 120 cm
Correct Answer:
90 cm
Explanation:
Given, f = + 30 cm and m = 1 / 4 Magnification, m = f / (f – u)
Therefore, 30 / (30 – u) = 1 / 4
30 – u = 120
⇒ u = -90 cm