Calculate the distance at which an object should be placed in front of a convex lens of focal length 10 cm to obtain a virtual image of double its size.

Calculate the distance at which an object should be placed in front of a convex lens of ocal length 10 cm,so as to obtain an image twice the size of the object?

The image distance of an object placed 10 cm in front of a thin lens of focal length + 5 cm is

An object placed 10 cm in front of a convex lens of focal length 15 cm. The image produced will be

At what distance should be placed from a convex lens of focal length 15 cm to obtain an image three times the size of the object?

At what distance should an object be placed from a convex lens of focal langth 15 cm to obtain an image three times the size of the object ?

Calculate two possible distances of an object from a convex lens of focal length 20 cm so as to obtain an image of double the size of the object.