[" 12.Calculate the focal length of a convex lens which produces a virtual image at a distance of "50cm" of an object "],[" placed "20cm" in front of it."]

Calculate the focal length of a convex lens which produces a virtual image at a distance of 50 cm of an object placed 20 cm in front of it.

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 is placed in contact with a convex lens of focal length 25 cm . The combination produces a real image at a distance of 80 cm , when an object is at a distance of 40 cm . What is the focal length of concave lens ?

A concave lens is placed in contact with a convex lens of focal length 25 cm . The combination produces a real image at a distance of 80 cm , when an object is at a distance of 40 cm . What is the focal length of concave lens ?

A lens with a focal length of 25 cm produces real image of an object at a distance of 50 cm from the lens. At what distance the object placed from the lens?

The focal length of convex lens is 20 cm. If an object of height 4 cm is placed at a distance of 30 cm from the lens, find: The position of the image