An object of size 3.0 cm is placed 14cm in front of a concave lens of focal length 21cm. Describe the image produced by the lens. What happens if the object is moved further away from the lens?
Given:
h₁=3cm;u=−14cm;f=−21cm
By lens formula, 1/v−1/u=1/f
1/v−1/−14=1/−21
v=−8.4cm
Now, Magnification formula for lens,
m=h/′h=v/u
h₂=8.4×3/14
⇒h2=1.8cm
If the object is moved further away from the lens, the image will continue to move towards the lens and the size of the image will decrease with an increase in the distance.