Question

An object is placed at a distance of 15 cm from a concave lens of focal length 6 cm find the location nature and size of the image

Answer 1

Answer:

question is incomplete either height of image or height of object is required.

Answer 2

answer : image distance, v = -30/7 ≈ -4.3 cm , size of image is smaller than that of object i.e., 2/7 times of object.

object distance, u = -15cm

Focal length of concave lens, f = -6cm

using lens maker formula, 1/v - 1/u = 1/f

⇒1/v - 1/-15 = 1/-6

⇒1/v + 1/15 = -1/6

⇒1/v = -1/6 - 1/15 = (-5 - 2)/30

⇒v = -30/7 ≈ -4.3 cm

image distance would be 4.3cm left side of the lens.

magnification, m = v/u

= (-30/7)/(-15)

= 2/7

size of image = 2/7 × size of object.

hence, image is smaller than object.