Question

An object of height 5cm is placed perpendicular to the principle axis of a convex lens of 'f' 10cm. If the distance of the object from 'o' is 20cm, determine the position, nature and size of the object​

Answer 1

Answer:Given :-

f = - 10 cm

u = - 20 cm

v = ?

Solution :-

Using, 1/f = 1/v - 1/u, we get

1/v = 1/f + 1/u

⇒ 1/v = 1/- 10 + 1/(- 20)

⇒ 1/v = - 2 - 1/20

⇒1/v = - (3/20)

⇒ v = - 20/3 cm

m = h/h' = v/u

h = v/u × h'

⇒ h = 20/3 × 20

⇒ h = 5/3

⇒ h = 1.6 cm.

Hence, The position of the image is 1.6 cm.

Image if virtual and diminished.

Explanation: