Analysis of test questions: (1) Examination: Hold the mirror arm with your right hand, take out the microscope from the mirror box, hold the mirror holder with your left hand, and gently put it on the experimental table. First, check whether the parts of the microscope are damaged. If you find any damage or poor performance, report it to the teacher immediately for treatment.
(2) Preparation: Place the microscope on the left side of the front plane, and tilt the lens barrel (some microscopes have been tilted) for observation if necessary. Turn the coarse adjustment knob to slightly raise the lens barrel (or lower the stage) and slightly increase the distance between the objective lens and the stage. Then rotate the objective lens converter and aim the low-power lens at the light hole in the center of the stage (click can be heard).
(3) Aiming at the light: open the aperture, lift the condenser, open both eyes at the same time, look into the eyepiece with the left eye, and adjust the direction of the reflector at the same time until the light in the field of vision is bright and uniform. The flat mirror of the reflector is easy to bring other scenery into view, and concave mirror is generally used to aim at the light.
(4) Placement of the slide specimen: place a slide specimen on the stage with the specimen cover facing upwards, place the specimen in front of the stage, then push it under the objective lens and press it with a tabletting clamp. If there is a specimen shifter, clamp the specimen with the spring on it, and then move the part to be observed to the center of the light hole.
(5) Adjusting the focal length: Turn the coarse adjuster counterclockwise with your left hand, so that the objective table slowly rises to a position where the objective lens is about 5 mm away from the specimen. Be careful not to observe on the eyepiece when you climb the stage. Be sure to observe that the stage rises from the right to avoid excessive rise and damage to the lens or sample. Then, open your eyes at the same time, look at the objective lens from the side of the microscope, and rotate the coarse adjustment button at the same time, so that the lens barrel slowly descends (or the stage rises). When the distance between the low-power lens and the glass slide is about 5mm, observe the visual field from the eyepiece with the left eye, and slowly turn the coarse adjustment button with the left hand to make the lens barrel rise slowly until an object image appears in the visual field. If the object image is not clear, turn the fine-tuning button to make the object image clearer. So choose: c, d.