An object 2.4 m in front of a lens forms a sharp image on a film 12 cm behind the lens. A glass plate 1 cm thick, of refractive index 1.50 is interposed between lens and film with its plane faces parallel to film. At what distance (from lens) should object shifted to be in sharp focus of film?

An object 240 cm in front of a lens forms a sharp image on a screen 12 cm behind the lens. A glass slab 1 cm thick, having refractive index 1.50 is placed between the lens and the screen with its refracting faces perpendicular to the principal axis of the lens. (a) By how much distance the object must be moved so as to again cast a sharp image on the screen? (b) Another identical glass slab is interposed between the object and the lens. How much further the object shall be moved so as to form a sharp image on the screen.

An object placed 10 cm in front of a lens has an image 20 cm behind the lens. What is the power of the lens ( in dioptres ) ?

An object is placed 12cm in front of a lens to form an image on a screen. The size of the image is twice that of the object. What is the distance between the object and the image?

An object is placed 12cm in front of a lens to form an image on a screen. The size of the image is twice that of the object. What is the distance between the object and the image?

A point object is placed at a distance of 25cm from a convex lens. Its focal length is 22cm. A glass slab of refractive index 1.5 is inserted between the lens and the object, then the image is formed at infinity. Find the thickness of the glass slab (in cm).

A point object is placed at a distance of 25cm from a convex lens. Its focal length is 22cm. A glass slab of refractive index 1.5 is inserted between the lens and the object, then the image is formed at infinity. Find the thickness of the glass slab (in cm).