A thin concave lens of focal length is used to form images of real objects placed at…
PHYSICS · Multi-part · CBSE · Physics · Light — Reflection and Refraction · Light — Reflection and Refraction
Problem
A thin concave lens of focal length f is used to form images of real objects placed at different positions on its principal axis.
(i) Draw neat, well-labelled ray diagrams for the following four cases:
(1) the object at infinity,
(2) the object beyond 2F,
(3) the object at F,
(4) the object between F and the optical centre O. In each diagram mark the position and relative size of the image.
(ii) From the diagrams drawn in part (i), explain with proper reasoning why a concave lens always produces a virtual, erect and diminished image, irrespective of where the object is placed on the principal axis.