What kind of light microscope can be used to see the surface condition of 0 125 mm glass fibers?

Millimeter yarn (125 microns) is very coarse, generally fiberglass, more than 9 m is roving; 125 m yarn, with 50 100 times is enough, we produce, sometimes for convenience, will directly use a 30 100 times magnifying glass to observe the situation of glass fiber filament on the spot, to see scratches, defects, bubbles, etc., because the glass fiber has a coating, it is easy to see. Click for product details

Optical microscope (abbreviated as OM) is an optical instrument that uses optical principles to magnify and image tiny objects that cannot be distinguished by the naked eye, so that people can extract microstructural information.

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A microscope for a general student will do.

A millimeter magnification of 100 times is fine.

It's clear. Don't ask for anything special.

If there is a scratch, the refraction of light is not the same as the rest of the place.

A 100x portable measuring microscope is sufficient.

Its practical stereo microscope is also possible.

Hello, the optical microscope can only see the micrometer, which is obtained from experiments and data, for the following reasons: the wavelength of visible light is 770 390 nanometers, and the resolution of the optical microscope is closely related to the focus range of the illuminated beam. In the 70s of the 18th century, the German physicist Ernst.

Abbe discovered that visible light is not fractured due to its wave-free nature, so the beam cannot be infinitely focused. According to this Abbe's law, the minimum diameter in which visible light can be focused is one-third of the wavelength of the light wave, which is 200 nanometers. For more than a century, 200 nanometers"Abbe Limit"It has long been considered the theoretical limit of resolution for optical microscopy, and objects smaller than this size must be observed with the help of an electron microscope limb or tunneling microscope.

b Chromatin.

Ribosomes have a membrane-free structure and are mainly composed of proteins (40%) and RNA (60%). Ribosomes are divided into two categories according to the sedimentation coefficient, one (70s) is found in prokaryotes such as bacteria and the other (80s) is found in the cytoplasm of eukaryotic cells. Some of them float inside the cell, and some of them clump together.

Chromatin was first proposed by Flemming in 1879 to describe substances that are strongly colored after staining in the nucleus. Chromatin is now thought to be the substance in the nucleus of the intercellular phase that can be stained with basic dyes. The basic chemical component of chromatin is the deoxyribonucleic acid nucleoprotein, which is a complex of DNA, histones, non-histones, and a small amount of RNA.

b Chromatin. The magnification of ordinary light microscopes is relatively small, so the specific structure of each organelle or nucleus in the cell cannot be seen, and can only be seen under an electron microscope.

D ribosomes are 10-20 nm in size and can only be observed with an electron microscope.

Answer B Analysis: This question is to examine the imaging characteristics of the microscope, and you can write Chinese characters or letters on the glass slide to understand it in a rough way

Answer: The microscope is an inverted image, the handstand is not the opposite, not upside down, not left and right, is upside down, left and right are upside down, that is, the key is the image obtained after rotating 180 ° The easier way is to write the letters or Chinese characters to be observed on the paper and look upside down, that is, rotate 180°, which is the image seen in the microscope

Therefore, selection: b Comments: The key to answering this question is to understand that the imaging characteristics of the microscope are that the microscope is an inverted image To understand that the "inverted" hole in the draft is not the opposite, it is the image obtained after rotating 180°

Answer B examines the types and functions of microscopes, in which the optical microscope can only see the microstructure of the cell, but not its submicroscopic structure, and the submicroscopic structure can only be used with the help of an electron microscope. In this question, sucrose molecules, ribosomes, and bacteriophages cannot be seen with a light microscope, and although the chromosomes are submicroscopic structures, they can be seen with an optical microscope after being stained with basic dyes. Observing the separation of the plasma wall and the flow of the cytoplasm with an optical microscope is a phenomena that can be used to infer abstract knowledge.

This question is more difficult.

a. The image of the object seen by the microscope is not only upside down, but also upside down There is a small trick to do this kind of problem, which is to write the letter seen under the microscope on a small piece of paper, and then rotate the paper 180 degrees and then look at the image upside down and left If the object observed in the field of view of the microscope is "b", then the object on the glass slide is "q", so this item is incorrect

b. The lens barrel is lowered to make the objective lens slowly approach the glass slide, and the two eyes should be fixed on the objective lens to prevent the objective lens from crushing the slide, so this item is correct;

c. When placing the microscope, in order to facilitate the observation of the left eye, the microscope should be placed on the left side of the experimental table, about 7 cm away from the edge, so this item is correct;

d. The magnification of the microscope refers to the magnification of the length or width of the object to be observed, which is expressed by the product of the magnification of the eyepiece and the objective lens, so this item is correct;

Therefore, a