The microscope is the device intended for increase in images and also for measurement of the objects or details badly visible or at all invisible with the naked eye. To make it it is correct, it is necessary to know extent of increase in a microscope.
Instruction
1. The microscope consists of basic elements: eyepiece and lens. They are fixed in a mobile tube which fastens on the metal basis. On the same basis the subject table is located. Also in modern microscopes most often there is a lighting system allowing to consider better the studied subject.
2. The lens is an optical device which projects the image on the plane. He is responsible for useful increase in an object. Most often the lens consists of several lenses. Increase in a lens is approximately equal to the relation of optical length of a microscope to the main focal length of f about. lens. Increase is always designated on a lens by figures. The most often used lenses at development of the school program – h8 and h40.
3. The eyepiece is a part of a microscope which is turned to an eye. It is intended for examining with some increase in the image which gives a lens. The eyepiece can consist of two or three lenses. Eyepieces do not help to reveal new details of the structure of the studied object, and in this regard their increase is useless. Increase in an eyepiece can be found as well as increase in any magnifying glass. It equals to the relation of the best sight (that makes 25 centimeters) to the main focal length of an eyepiece (f apprx.). Eyepieces with increase 7, 10, 15 are most often used. It is designated by figures on the eyepiece.
4. For finding of optical increase you will also need size σ. It is the optical length of a microscope which is equal to length between internal focuses of a lens and an eyepiece.
5. Proceeding from structure of a microscope, it becomes clear that the studied object is behind double focal length on other side of a lens. Thus, it is possible to define increase in a microscope, knowing increase in a lens and eyepiece. It will equal to their work (N=σ*25/f about. * f apprx.).