Displacement method for Lens

In case of displacement method of lenses, the product of magnification in both cases is

In the displacement method a conves lens is placed in between an object and a screen. If the magnificaiton in the two position are m_(1) and m_(2) ( m_(1) gt m_(2) ), and the distance between the two positions of the lens is x, the focal length of the lens is

Assertion: In displacement method of finding focal length of a convex lens its magnification in one position of lens is +2, then magnification in another position of lens should be -1/2. Reason:This method can't be applied for a concave lens.

In displacement method, the lengths of images in the two positions of the lens betwent the object and the screen are 9 cm and 4 cm respectively. The length of the object must be

Lens and displacement method

In a displacement method using lens, we obtain two images for separation of the lens d. One image is magnified as much as the other is diminshed . If m is the magnification of one image, find the focal length of the lens.

In the displacement method , a convex lens is placed in between an object and a screen . If one of them magnification is 3 and the displacement of the lens between the two positions is 24 cm , then the focal length of the lens is :-

In displacement method, convex lens forms a real image of an object for its two different positions. If heights of the images in two cases be 24 cm and 6 cm, then the height of the object is