A 5 cm tall object is placed perpendicular to the principal axis of a convex lens of focal length 20 cm. The distance of the object from the lens is 30 cm. Find the (i) position, (ii) nature, and (iii) size of the image formed.

A 5 cm tall object is placed perpendicular to the principal axis of a

1.	A 5 cm tall object is placed perpendicular to the principal axis of a convex lens of focal length 20 cm. The distance of the object from the lens is 30 cm. Find the (i) position, (ii) nature, and (iii) size of the image formed.
Answer» Solution :Here H = +5 CM, f = +20 cm, u = - 30 cm (i) Using lens FORMULA `(1)/(v) - (1)/(u) = (1)/(f)`, we have `(1)/(v) = (1)/(f) + (1)/(u) = (1)/((20)) + (1)/((-30))= (3-2)/(60) = (1)/(60)` `therefore` v = + 60 cm (ii) +ve sign of v means that image is being formed on the other side of lens i.e., the image is a real image. (iii) As `m = (h.)/(h) = (v)/(u)` `therefore""h. = (v)/(u) . h = ((+60))/((-30)) xx (+5) = - 10` cm