A concave lens has focal length 20 cm. At what distance should the object from the lens be placed so that it forms an image at 10 cm from the lens?

An object 60 cm from a lens gives a virtual image at a distance of 20 cm in front of the lens. What is the focal length of the lens? Is the lens converging or diverging? Give reasons for your answer.

A concave lens of 20 cm focal length has an object kept at a distance of 60 cm in front of the mirror. Compute the image distance.

Calculate the image distance for an object of height 12 mm at a distance of 0.20 m from a concave lens of focal length 0.30 m?

A concave lens has a focal length of 20 cm. At what distance from the lens a 5 cm tall object is placed so that it forms an image at 10 cm from the lens? Also calculate the size of the image formed.