A thin convex lens from a real Image of a certain object`'p'`times it size .The size of real image become`'q'`times that of object when the lens is moved nearer to the object by a distance'a'fin dfocal length of the lens?

A thin converging lens forms the real image of certain real object magnified m times.The magnification of real image become n when lens is moved nearer to object by distance x . find focal length of the lens

A convex lens forms a real image of the object when the lens is at a distance of 1 m from the object. The size of the image is 3 times that of the object. The position of the object and the screen are kept fixed but the distance of lens from the object is doubled. The image is now one half of the size of the object, the focal length of the lens is

A convex lens of focal length f produces a real image 3 times as that of size of the object, the distance between the object and the lens is

A convex lens of focal length f produces a real image 3 times as that of size of the object, the distance between the object and the lens is

A convex lens of focal length f produces a virtual image n times the size of the object. Then the distance of the object from the lens is

A convex lens of focal length f produces an image 1/n times than that of the size of the object. The 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