Where should an object be placed before a convex lens so that a real image of the same size as the object is formed ?

An air bubble inside water. The refractive index of water is 4/3 . At what distance from the air bubble should a point object be placed so as to form a real image at the same distance from the bubble:-

A plano convex lens of refractive index 1.5 and radius of curvature 30cm. Is silvered at the curved surface. Now this lens has been used to form the image of an object. At what distance from this lens an object be placed in order to have a real image of size of the object.

An object is there on a wall. Now by help of convex lens, an image of object is obtained of same size as of object on the opposite parallel wall. If the lens is at distance d from second wall, then what should be the focal length of lens ?

A point object is placed on the axis in front of a convex lens of focal length 30 cm. The distance of the object from the lens is 45 cm. If the lens is moved away from object by 1 mm and also the object is moved apart from the line joining the object and optical centre by 1 mm the displacement of the image has magnitude-

The redius of curvature of the convex face of a plano-convex lens is 12cm and its refractive index is 1.5. a. Find the focal length of this lens. The plane surface of the lens is now silvered. b. At what distance form the lans will parallel rays incident on the convex face converge? c. Sketch the ray diagram to locate the image, when a point object is places on the axis 20cm from the lens. d. Calculate the image distance when the object is placed as in (c).

The image of an object, formed by a plano-convex lens at a distance of 8 m behind the lens, is real is one-third the size of the object. The wavelength of light inside the lens is 2/3 times the wavelength in free space. The radius of the curved surface of the lens is

The focal length of a concave mirror is 30 cm.Find the position of the object in front of the mirror,so that the image is three times the size of the objects.

In the human eye, the image of an object is formed at the ........

(a) For the telescope described in Exercise 9.28 (a), what is the separation between the objective lens and the eyepiece? (b) If this telescope is used to view a 100 m tall tower 3 km away, what is the height of the image of the tower formed by the objective lens? (c) What is the height of the final image of the tower if it is formed at 25cm?