Question

An object is placed on principal axis at a distance of 20cm before a convex lens of focal length 15cm. State the nature of the image and its position, show with a ray diagram.​

Answer 1

Answer:

u = -20cm

f = 15 cm

v = ?

using lens formula :    1/f =1/v - 1/u

                                    1/15 = 1/v - ( 1/-20)

                                     1/15 = 1/v + 1/20

                                     1/v = 1/20 - 1/15

                                      1/v =  -1 / 60

                                       v = 60 cm

                  hence the  the image is virtual , erect and enlarged