Question

If an object of 5 cm is placed at a distance of 15 cm from a convex lens of focal length 10 cm find the position nature and height of the image

Answer 1

Given :-

• Object distance (u) = -15cm
• Object height (h) = 5cm
• Focal length (f) = 10cm
• Image distance (v) = ?
• Image height (h') = ?

Lens Formula :- 1/v - 1/u = 1/f

1/v = 1/f + 1/u

1/v = 1/10 + 1/(-15)

1/v = 1/10 - 1/15

1/v = (15-10)/150

1/v = 1/30

1/v = 1/30

v = 30cm

•°• Image is formed 30cm in front of mirror.

Magnification, M = h'/h = -v/u

h'/5 = -30/15

5(-30) = 15(h')

-150 = 15h'

h' = -150/15

h' = -10