A concave lens of focal length 15 cm forms an image 10 cm from the lens. How far is the object placed from the lens ?

An object of size 3.0 cm is placed 14 cm in front of a concave lens of focal length 21 cm. Describe the image produced by the lens. What happens if the object is moved further away from the lens?

An object 3.0 cm high is placed perpendicular to the principal axis of a concave lens of focal length 7.5cm. The image is formed at a distance of 5 cm from the lens. Calculate (i) distance at which object is placed and (ii) size and nature of image formed.