Question

draw a labelled diagram for the formation of image by a convex lens of focal length 10 centimetre when the object is placed distance 25 CM of other lines determine the size of the image formed if size of the object is 4 centimetre​

Answer 1

focal length f=10cm

object distance u=-25cm

image distance v=?

size of object h1=4cm

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

1/v-1/-25=1/10

1/v=1/10-1/25

1/v=5-2/50

1/v=3/50

v=50/3

v=16.67cm

magnification, m=v/u

m=16.67/-25

m=-0.66

Now

m=h2/h1

-0.66=h2/4

h2=-0.66×4

h2=-2.64cm