What are the structures in the microscope that can make the lens barrel rise and fall, which one is

Quasi-focal spiral. There is a collimation helix behind the lens barrel, including a coarse collimation helix and a fine collimation helix Coarse collimation spiral: the amplitude of the lifting of the lens barrel is large when it is rotated; Fine Quasifocal Spiral: The amplitude of the lifting of the lens barrel is small when rotating.

Microscopes generally have three objective lenses, i.e., low magnification, high magnification, and oil lens, which are fixed in the hole of the adapter plate of the connecting objective. When observing specimens, a low-magnification objective lens is used first, at this time, the field of view is larger, and the specimen is easier to detect, but the magnification is small (generally 100 times magnification), and the structure of smaller objects is not easy to observe. The magnification of the high-magnification objective lens is large (usually 400 times magnification) and can observe small objects or structures.

Use of microscopes.

When using natural light sources for microscopic inspection, it is best to use a light source facing north, and direct sunlight is not appropriate; When using artificial light sources, fluorescent lamps should be used.

of light sources. During the microscopic examination, the body should be facing the practice table, adopt a correct posture, open the eyes naturally, observe the specimen with the left eye, observe the recording and drawing with the right eye, and adjust the focus with the left hand at the same time to make the object clear and move the specimen field of vision. Right-handed recording and drawing.

The stage should not be tilted during microscopic examination, because when the stage is tilted, liquid or oil tends to flow out, which not only damages the specimen, but also contaminates the stage, and also affects the examination results.

In the microscope, the structure that can make the lens barrel lift has a coarse collimation spiral and a fine collimation spiral, wherein the coarse collimation spiral can make the lens barrel lift obviously, and the object image can be found by adjusting the coarse collimation spiral, and the fine collimation spiral can only be fine-tuned to adjust the clarity of the object image.

The descent is to adjust the distance from the objective to the slide so that it is more imaged. Because the object (glass slide) of the objective lens is between the focal length of 1x and 2x of the objective lens, according to the imaging law of the convex lens.

Between 1x and 2x focal lengths, the smaller the object distance, the larger the image.

The ascent is to adjust the distance from the scope to the slide to make the image clearer, because the objective lens is the actual object of the eyepiece, which is located close to the focal point within 1 x the focal length in front of the eyepiece. According to the imaging law of convex lens, within one time of the focal length, the farther the object distance, the larger the image distance, and the larger the image, so the lens barrel should be raised accordingly.

This is my understanding.

By the time the film was placed, the lens barrel had already gone up.

If we look directly from top to bottom, we are looking at the eyepiece, and it is very easy for the objective lens and the slide to collide when descending, which can damage the objective lens and crush the slide.

Answer: C: The coarse collimator spiral is a large lifting of the lens barrel, and the fine collimation spiral is a small lifting of the lens barrel.

Coarse Adjuster (Coarse Spiral): The large spiral is called the Coarse Adjuster, which can make the lens table rise and fall quickly and relatively large when moving, so it can quickly adjust the distance between the objective lens and the specimen to make the object image appear in the field of view.

Fine Regulator (Fine Alignment Spiral): The small spiral is called the fine regulator, which can make the lens table slowly rise and fall when moving, and is mostly used when using a high-magnification lens, so as to obtain a clearer image of the object, and to observe the structure of different levels and different depths of the specimen.

Both the coarse collimator and the fine collimator can adjust the lens barrel, the coarse collimator makes the lens barrel rise or fall relatively largely, and the amplitude of the lens barrel rises and falls less when the fine collimator spiral uses the coarse collimator spiral to find the object image, and let the fine collimator make the object image clear

Therefore, a

1) The adjustment method of the brightness of the microscope field of view is: the light passing through the small aperture is less, the field of view is dark, and the flat rock embedded mirror can only reflect the light and cannot change the light intensity, so the adjustment with a small aperture and a plane mirror will darken the field of vision; A large aperture passes through a lot of light, a bright field of view, and a concave mirror.

The light is concentrated, which can improve the brightness of the field of vision, so the rough and concave lens is adjusted with a large aperture and a concave mirror, which will brighten the field of view According to the above analysis, it can be seen that when using a microscope, the structure to adjust the intensity of light is the aperture and the reflector.

In the picture, it's a reflector

2) When turning, it is the fine collimation spiral that makes the lifting range of the lens barrel smaller 3) The lens that approaches the object of observation is the objective lens

4) When the light is aligned, the converter should be rotated first to align the low magnification lens with the clear hole, and then turn the light shield to align a larger aperture with the clear hole

So the answer is: (1) ; Reflectors

2）⑦；Fine collimation spiral

3）③；Objective

4）②；Converters

(1) 8. Coarse quasi-focal spiral can lift and lower the lens barrel in a large range;

2) The calculation of the magnification of the microscope is the magnification of the eyepiece multiplied by the magnification of the objective, and when observed with the eyepiece of "10x" and the objective lens of "40x", the magnification is 10 40 400x;

3) Because the object we see under the microscope is an upside down image, the image is upside down, left and right, therefore, if we see a "b" in the field of view of the microscope, the "up" q written on the slide should be an inverted "up" Q;

4) The method of adjusting the brightness of the microscope field of view is as follows: the light passing through the small aperture is less and the field of vision is darker, and the plane mirror can only reflect the light and cannot change the light intensity, so the field of view will be darkened by adjusting it with a small aperture and a plane mirror; The light passing through the large aperture is bright in multiple fields, and the concave mirror makes the light converge and the brightness of the field of view is enhanced, so the adjustment with a large aperture and concave mirror will brighten the field of vision;

5) After replacing the low magnification lens with a high magnification, the magnification of the microscope increases, the number of cells seen decreases, and the volume of cells increases; At this point, less light enters the field of view and the field of view becomes darker

Therefore, the number of cells, their size, and the field of view observed with a high-power microscope compared to those observed with a low-magnification microscope are in the following order: decrease, enlarge, and darken

So the answer is: (1) 8; coarse quasi-focal spiral;

2) 400 times;

3）q；4) Large aperture; concave mirrors;

5) dark; Big; Small

(1) F coarse quasifocal spiral is relatively coarse, and the range of lifting and lowering the lens barrel is large, and 2 fine collimating spiral is relatively thin, and the range of lifting and lowering lens barrel is small;

2) As can be seen from the figure, C is the objective lens and E is the reflector

3) When taking the microscope, the part where the right hand holds the mirror is the H mirror arm (4) The use of the microscope should be done: first use a low magnification lens, and then use a high magnification lens; Adjust the coarse collimation spiral first, and then adjust the fine alignment spiral

5) The adjustment method of the brightness of the microscope field of view is as follows: the light passing through the small aperture is less, the field of view is dark, and the plane mirror can only reflect the light and cannot change the light intensity, so the field of view will be darkened by adjusting it with a small aperture and a plane mirror; There is a lot of light passing through a large aperture, and the field of view is bright, and the concave mirror makes the light converge and can improve the brightness of the field of view, so adjusting it with a large aperture and a concave mirror will brighten the field of view According to the above analysis, it can be seen that when using a microscope, the structure that adjusts the intensity of light is the aperture and the reflector

So the answer is: (1)f; coarse quasi-focal spiral;

2) objective lens; Reflectors

3）h；Mirror arm;

4) Low; High;

5) Adjust the aperture; Reflectors