Magnification of the red objective lens of an optical microscope
The red objective lens of an optical microscope represents a magnification of 4 times, yellow represents 10 times, blue represents 40 times, and white represents 100 times. Multiply the eyepiece magnification by the objective lens magnification to get the total magnification of the microscope.
The "10" and "4" in the upper numbers of an optical microscope indicate that the magnification of the objective lens is 10 times or 4 times. The magnification here is not the magnification of the area, but the magnification of the length or width of the image, and the total size of the microscope The magnification is equal to the product of the magnification of the objective lens and the eyepiece, and the magnification of the objective lens is proportional to its length. The greater the objective magnification, the longer the objective lens.
Optical microscope parameters
The working distance of the objective lens of an optical microscope is related to the focal length of the objective lens. The longer the focal length of the objective lens, the lower the magnification, and the longer the working distance. Example: The 10x objective lens is marked with 10/0.25 and 160/0.17, where 10 is the magnification of the objective lens. 0.25 is the numerical aperture; 160 is the length of the lens barrel (in mm); 0.17 is the standard thickness of the cover glass (in mm).
The effective working distance of the 10x objective lens is 6.5mm, and the effective working distance of the 40x objective lens is 0.48mm. The function of the objective lens is to magnify the specimen for the first time. It is the most important component that determines the performance of the microscope and its resolution.
When the objective lens has clearly resolved the fine structure, if it has not been re-magnified by the eyepiece and cannot reach the size that the human eye can distinguish, it will not be seen clearly; but the fine structure that the objective lens cannot resolve, although it has been re-magnified by the high-power eyepiece, , it is still not clear, so the eyepiece can only act as a magnifier and will not improve the resolution of the microscope.
