Introduction of Microscopes

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An optical instrument which is used for seeing a magnified image of near and small objects that cannot be seen by a naked eye is called a microscope there are two types of microscope

1-     Simple microscope or magnifying Glass:-

2-     Compound Microscopes

Simple microscope or magnifying Glass:-

Definition:- An ordinary convex lens which is held close to the eye to magnify the image of an object is called a simple Microscopes  when this lens is placed between eye and object it helps us to see the details of an object by bringing it closer than

Principle:-if a small object is  placed with  in the principal focus of a convex lens i.e between the focal lenth of point and the lens avirtual erect and madnified image of the object is formed on the same side

Formation Of image:-if an object AB is placed in fornt of the eye least distance of distincit vision if the same object AB is placed with in the focal length f of convex lens at distance p so that the lens forms its magnified virtual and erect image

Magnifying power:-it is the ratio of the angle subtended at the eye by image to the angle  subtended by the objest at the unaided eye when both image and object are placed at the leastdistance of distinct vision

Compound Microscope:-] it is optical instrument which is used for higher magnification of small object which cannot be seen by unaided eye like germs

Construction:-it consists of two convex lenses the lens towards object is called objective and the other lens towards eye is called the eye piece.the focal length of the objective is ahort and the focal length of eyepiece is large the objective is fitted at one  end

Working:-the object is placed between principal focus and center of curvature of the object a real inverted and enlarged image is formed beyond on the other side the eye pieces is used  as a magnifying glass to see the image formed by the object


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