A concave lens of focal length 20 cm product an image half in size of the real object. The distance of the real object is

A concave lens of focal length f produces an image (1//n) times the size of the object. The distance of the object from the lens is :

A convex lens of focal length 16 cm forms a real image double the size of the object. The distance of the object from the lens is

A concave mirror of focal length f produces a real image n times the size of the object. The distance of the object from the mirror is

A convex lens of focal length 16 cm forms a real image double the size of the object. The image distance of the object from the lens is

A concave lens of focal length (1)/(3)m forms a real, inverted image twice in size of the object. The distance of the object from the lens is

A convex lens of focal length 8 cm forms a real image of the same size as the object. The distance between object and its image will be:

A concave mirror of focal length f produces a real image n time the size of the object.What is the distance of the object from the mirror.