A concave lens produces an image 20 cm from the lens of an object placed 30 cm from the lens. The focal length of the lens is:

Find the focal length of a convex lens which produces a real image at 60 cm from the lens when an object is placed at 40 cm in front of the lens .

Find the focal length of a convex lens which produces a real image at 60 cm from the lens when an object is placed at 40 cm in front of the lens.

Find the focal length of a convex lens which produces a virtual image at 10 cm from the lens when an object is placed at 5 cm from the lens.

Find the focal length of a convex lens which produces a virtual image at 10 cm from the lens when an object is placed at 5 cm from the lens .

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 ?

The same size images are formed by a convex lens when the object is placed at 20cm or at 10cm from the lens. The focal length of convex lens is ____ cm

An object is placed at 50 cm from a lens produces a virtual image at a distance of 10 cm in front of the lens . What is the focal length of the lens ? Is it converging or diverging ?