The lens of a 35 mm camera has a focal length of 56 cm.
Also find the exposure time for f/4 if it is 1/500 seconds for the case(i)

An object of size 10 cm is placed at distance of 20 cm in front of aconcave lens of focal length 20 cm. Find the size and nature of image. Also find distance of image from the lens

A convex lens of focal length 20 cm is placed at a distance of 24 cm from the screen how far from the lens should an object be placed so as to from a real image on the screen. Also find the nature and magnification of the image produced.

A convex lens of refractive index 1.5 has a focal length of 18 cm in air.Calculate the change in focal length,when it is immersed in water of refractive index 4//3 .

A camera lens of focal length 5 cm is mounted on a fine screw thread for adjusting the focus.What range of movement is neede,if the amer ais to be able to take sharp photographs at 1 m as well as from great distances?

An astronomical telescope has an objective lens of focal length 20 m and eyepiece of focal lengh 1 cm. If this telescope is used to view the moon, find the diameter of the image formed by the objective lens given the diameter of the moon is 3.5 xx 10^6 m and radius of lunar orbit is 3.8 xx 10^8 m .

A concave lens has focal length of 15 cm. At what distance should the object from the lens be placed so that it forms an image at 10 cm from the lens? Also find the magnification produced by the lens.

An astronomical telescope has an objective lens of focal length 20 m and eyepiece of focal length 1 cm. Find the angular magnification of the telescope.

A convex lens has 12 cm focal length in air. What is its focal length in water? (Refractive index of air-water is (1.33) , refractive index for air-glass = (1.5) .