In displacement method distance of object and screen is 100 cm initial image is obtained on screen. Now lens is displaced `40 cm` image formed on screen again ` ` . If power of the lens is `(100/N)` dioptre, then find the value of `N`:

The distance between an object and the screen is 100cm. A lens produces an image on the screen when the lens is placed at either of the positions 40cm apart. The power of the lens is nearly

In displacement method, the distance between object and screen is 96cm. The ratio of lengths of two images formed by a converging lens placed between them is 4. Then,

In displacement method, there are two position of a lens for which we get clear image. First position of the lens is at 40 cm from object and second is at 80 cm, the focal length of lens is

In a displacement method the distance between the object and the screen is 70 cm and the focal length of the lens is 16 cm, find the separations of the magnified and diminished image position of the lens.

A convex lens is placed between an object and a screen which are at a fixed distance apart for one position of the lens. The magnification of the image obtained on the screen is m_(1) . When the lens is moved by a distance d the magnification of the image obtained on the same screen m_(2) , Find the focal length of the lens.

A convex lens is used to obtain a magnified image of an object on a screen . The object is at a distance 10 m from the lens . If the magnification is 19. the focal length of the lens is

A converging lens is used to form an image on a screen. When the upper half of the lens is covered by an opaque screen

A converging lens is used to form an image on a screen. When the upper half of the lens is covered by an opaque screen

A converging lens is used to form an image on a screen. When the upper half of the lens is covered by an opaque screen

A convex lens forms an image of an object on a screen. The height of the image is 9 cm . The lens is now displaced until an image is again obtained on the screen. Then height of this image is 4 cm . The distance between the object and the screen is 90 cm.