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 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 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 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 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 25 cm from a convex lens of focal length 20cm. If a glass slab of thickness t and refractive index 1.5 is inserted between the lens and the object, the image is formed at infinity. The thickness t is

An object placed at 20 cm from a lens, forms an image on a screen placed 60 cm on the other side of the lens. What is the focal length and type of the lens ?

A point object O is placed at a distance of 41 cm from a convex lens of focal length f = 20 cm on its principal axis. A glass slab of thickness 3 cm and refractive index mu = 1.5 is placed between the lens and the object with its faces perpendicular to the principal axis of the lens. Image of the object is formed at point I_(1) . Now the glass slab is tilted by an angle of theta = 1° (as shown in the Figure) and the final image is formed at I_(2) . Calculate the distance between points I_(1) and I_(2) . Consider only paraxial rays for the lens and near normal incidence for the glass slab.