A screen is placed 90 cm from an object. The image of the object on the screen is formed by a convex lens at two different locations separated by 20 cm . Determine the focal length of the lens.

An object is placed 40 cm from a concave mirror of focal length 20 cm, the image formed is

An object is placed at 20 cm from a convex mirror of focal length 10 cm. The image formed by the mirror is

A screen is placed a distance 40 cm away from an illuminated object. A converging lens is placed between the source and the screen and it is attempted to form the image of the source on the screen. If no position could be found, the focal length of the lens

A 5 cm high object is placed at a distance of 25 cm from a converging lens of focal length of 10 cm. Determine the position, size and type of the image.

An object 1.5 cm is size is placed on the side of the convex lens in the arrangement (a) above. The distance between the object and the convex lens is 40 cm. Detemine the maguificatin produced by the two-lens system an the size of the image.

Two convex lenses each of focal length 10 cm, are placed at a separation of 15 cm with their principal axes coinciding. (a) Show that a light beam coming parallel to the principal axis diverges as it comes out of the lens system. (b) Find the location of the virtual image formed by the lens system of an object placed far away. (c ) Find the focal length of the equivalent lens.

A concave mirror forms an image of 20 cm high object on a screen placed 5.0 m away from the mirror. The height of the image is 50 cm. Find the focal length of the mirror and the distance between the mirror and the object.