Question

An object of height 2cm is placed at the distance of 30cm from a convex lens of focal length 10 cm find the position, nature and height of object

Answer 1

Given:
⇒ Height of object, H(object) = 2cm
⇒Object distance, U = 30cm
⇒ Focal length, f = 10cm

To find: 
⇒ Position of image, V =?
⇒Height of image, H(image) =?
⇒Nature of image =?

Solution:
By using lens formula, 1/f = 1/v - 1/u we get, 

⇒ 1/10 = 1/v - 1/-30
⇒ 1/v = 1/10 - 1/30
⇒ 1/v = 1/15
⇒ ∴ v = 15cm

By using magnification formula, v/u = h(image)/h(object) we get, 

⇒ 15/-30 = h(image)/2
⇒ h(image) = 2 × (-1/2)
⇒ h(image) = -1cm

⇒ Image thus formed is Real and Inverted.
⇒ It is a Diminished image.


:)