The image obtained iwth a convex lewns is ereect and its length is four times the length of the object.If the focal length of the lens is 20 cm,calculate the object and image distance.

The image obtained with a convex lens is erect and its lenth is four times the length of the object.If the focal length of the lens is 20 cm,calculate the object and image distance.

The image formed by the lens is erect and its length is three times the length of an object. If the focal length of the lens is 15 cm, what kind of lens it is ? Calculate the object and image distance.

A convex mirror forms an imge,which is 1//n times the size of the object .If the focal length of the mirror is f,the distance of the object is

A lens of focal length 12 cm forms an upright image three times the size of a real object ,calculate the object and image distances.

The focal length of a convex lens is 30 cm and the size of image is quarter of the object.Them,the object distance is

If the distance between the screen and object is 50 cm and the displacement of the lens is 10 cm,clculate the focal length of the lens.

The graph between object distance u and image distance v for a lens is given below. The focal length of the lens is. .

Show that a convex lens produces an N times magnified image,when the object distances from the lens have magnitude (f+- f//N) .Here,f is the magnitude of the focal length of the lens.Hene,find the two values of object distance,for which a convex lens of power 2.5 D will produce an image that is four times as large as the object.