Question

an object of 4 cm is kept at 20 cm away from convex lenc of focal length 10 cm find position size and nature of an object

Answer 1

H= 4 cm

U= 20 cm

F= 10 cm.

According to lens formula,,

1/V - 1/U = 1/F

1/v = 1/f + 1/u

1/v = 1/10 - 1/20

1/v = -1/20

V = -20

We have, m = v/u

                   = -20/-20 = 1

Also, m= h'/h  ( where h = height of object and h'= height of image)

1=h'/4

h' = 4X1 = 4 cm.

Therefore, the image is real and inverted.