Optical instruments have application in human life. A simple microscope is used to view small objects clearly while the telescope is used to view distant objects. The main objective of those instruments is to see the objects better and completely . And this note provides us with an information about defects of vision in human eyes .
This note provides us with an information about microscope .compounds microscope consists of two converging lenses arranged co-axially. The lens facing to the object is called the objective and that closer to the eye is called eyepiece and simple microscope simply a magnifying glass or converging lens of short focal length. The lens is held slightly nearer the object than its focal length and the eye is positional close to the other side of lens .
This note provides an information about telescope and camera .Telescope are the different type the are Astronomical teliscope ,terrestrial telescope ,Galilean etc andA photographic camera consists of a converging lens system at one end of a light proof box and light-sensitive film at the other end .