An object is placed first at infinity and then at 20 cm from the object side focal plane of a convex lens. The two images thus formed are 5 cm apart the focal length of the lens is

An object is kept at 60 cm in front of a convex lens. Its real image is formed at 20 cm from the lens . Find the focal length and power of the lens.

A convex lens of focal length 10cm and concave lens of focal length 20 cm are kept 5 cm apart. The focal length of the equivalent lens is

An object is kept at 20 cm in front of a convex lens and its real image is formed at 60 cm from the lens . Find The focal length and power of the lens .

A convex lens is coaxially placed with a concave lens. A screen is placed at a distance of 100 cm apart from the combination. The focal length of convex lens is 15 cm. Determine the focal length of the concave lens if image of object placed at a distance of 20 cm, from the combination, is projected on the scrcen.

A screen is placed 90 cm from an object. The image an object on the screen is formed by a convex lens two different locations separated by 20 cm. the focal length of the lens is

An object is placed at a distance of 20 cm from a convex lens of focal length 10 cm . The image is formed on the other side of the lens at a distance

An object is placed at a distance of 15 cm from a convex lens.If the focal length of the lens is 60cm,find the image distance.

A screen is placed 90 cm from an object. The image of the object on the screen is formed by a convex lens at two different positions separated by 20 cm. Calculate the focal length of the lens.