An object is placed on the principal axis of a concave mirror at a distance of 1 . 5 f ( f is the focal length). The image will be at,

Step-by-step solution

Given, u = - 1 . 5 f , now use the mirror formula for the concave mirror, in terms of distance between object and pole, the distance between image and pole and focal length, 1 u + 1 v = 1 f ⇒ 1 - 1 . 5 f + 1 v = 1 - f ⇒ 1 v = - 1 f + 1 1 . 5 f ⇒ 1 v = - 1 . 5 + 1 1 . 5 f = - 0 . 5 1 . 5 f ⇒ v = - 3 f .