Question

An object is placed at a distance of 30 cm from a concave lens of focal length 15 cm. List four characteristics (nature, positions, etc.) of the image formed by the lens.

Answer 1

concave lens produces a virtual, erect diminished image.

Using Real Is Positive RIP Convention, u=30 and f=-15

$1/u+1/v=1/f$

$1/30+1/v=-1/15$

$1/v=-1/15-1/30=-3/30=-1/10$

$v=-10M=v/u=-1/3$

So image is erect, virtual, 1/3 size of object, and 10 cm from the lens, (between lens and object)