A real image of an object is formed at a distance of 20 cm from a lens. On putting another lens in contact with it, the image is shifted 10 cm towards thed combination. The power of the lenses is

A real image of an object is formed at a distance of 20 cm from a lens. On putting another lens in contact with it, the image is shifted 10 cm towards the combination, Determine the power of the second lens.

A lens forms real image of an object 20 cm away from lens. A second lens is kept in contact with this lens, then image shifts 10 cm towards the lens combination. Find the power of another lens.

A convex lens forms an image of a distant obj ect at distance of 20 cm from it. On keeping another lens in contact with the first, if the 40 image is formed at a distance of 40/3 cm from the combination, then the focal length of the second lens is

A combination of two thin lenses with focal lengths f_(1) and f_(2) respectively forms and image of distant object at distance 60cm when lenses are in contact. The position of this image shifts by 30 cm towards the combination when two lenses are separated by 10 cm . The corresponding values of f_(1) and f_(2) are

Ray coming from an object situated at infinity, fall on a convex lens and an image is formed at a distance of 16 cm from the lens. When a concave lens is kept in contact with the convex lens, the image is formed at a distance of 20 cm from the lens combination. Calculate the focal length of the concave lens.

A convex lens forms an image of an object on a screen 30 cm from the lens. When the lens is moved 90 cm towards the object, then the image is again formed on the screen. Then, the focal length of the lens is

An object kept at a distance of 30 cm from a lens, has its image formed at 20 cm from the lens and on the same side as the object. What is the focal power of the lens ?

A point object is placed at a distance of 15 cm from a convex lens. The image is formed on the other side of lens at a distance 30 cm from lens. When a concave lens is placed in contact with convex lens, image is shifted away further by 30 cm. calculate the focal lengths of the two lenses.

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