Question

An object is placed at a distance of 20 cm of height 5 cm Infront of a convex lens of focal length

15 cm. Find

(a) Position, nature and height of the image.

(b) draw its ray diagram​

Answer 1

Answer:

Radius of curvature (R) = 30 cm

f = R/2 = 30/2 = 15 cm

u = -20 cm,

h= 5 cm.

1/v +1/u = 1/f

1/v = 1/15+ 1/20 = 7/60

v = 60/7 = 8.6 cm.

Image is virtual and erect and formed behind the mirror.

hi/h0= v/u

hi/5= 8.6/20

hi = 2.2 cm.

Size of image is 2.2 cm.