# Images formed by a concave lens:

(i) Position of object: At ∞

Image: At Focus (F)

Nature: Virtual & diminished                 

(ii) Position of object: Between ∞ and O

Image: Virtual, erect and diminished                

Note:-

(A) For convex lens:

(i) When object is placed beyond F or on F, the image formed is real and inverted.

(ii) When object is placed between F and O, the image formed is virtual and erect.

(B) For concave lens:

Image formed is always virtual and erect.

# New Cartesian sign conventions:

(i) All the distance are measured from the optical centre of lens.

(ii) The distances measured in the direction of incident light are takes as positive whereas those measured in a direction.

(iii) Height measured above the principal axis is taken positive whereas that measured below the principal axis is taken as negative.