Calculate the focal length of a convex lens which produces a virtual image at a distance of 60 cm of an object placed 20 cm in front of it.

A small object is so placed in front of a convex lens of 5 cm focal length that a virtual image is formed at a distance of 20 cm. Find the magnification.

Find the position and nature of the image of an object 8 cm high and 10 cm in front of a convex lens of focal length 6 cm.

An object is placed at a distance of 100 cm from a converging lens of focal length 50 cm.

(i) What is the nature of image?

(ii) What is the position of image?

A convex lens produces an inverted image magnified three times of an object placed at a distance of 15 from it. Calculate the image distance.