Why is the resolution of electron microscopes better than that of optical microscopes?
The magnification of an optical microscope is smaller than that of an electron microscope. An optical microscope can only observe microscopic structures such as cells and chloroplasts, while an electron microscope can observe submicroscopic structures, that is, the structure of organelles as well as viruses, bacteria, etc
An electron microscope projects an accelerated and focused electron beam onto a very thin sample, where the electrons collide with atoms in the sample and change direction, resulting in solid angle scattering. The size of the scattering angle is related to the density and thickness of the sample, so it can form images with different brightness and darkness. The images will be displayed on imaging devices (such as fluorescent screens, films, and photosensitive coupling components) after magnification and focusing.
Due to the very short de Broglie wavelength of electrons, the resolution of transmission electron microscopy is much higher than that of optical microscopy, reaching 0.1-0.2nm and magnification of tens of thousands to millions of times. Therefore, the use of transmission electron microscopy can be used to observe the fine structure of samples, and even to observe the structure of only one column of atoms, which is tens of thousands of times smaller than the smallest structure that can be observed by optical microscopy. TEM is an important analytical method in many scientific fields related to physics and biology, such as cancer research, virology, materials science, as well as nanotechnology, semiconductor research, and so on.
The highest magnification of an optical microscope
How many times magnification can an optical microscope achieve? It mainly relies on the objective lens to actually magnify the object, and the eyepiece to magnify the image magnified by the objective lens twice. The objective of an optical microscope can only reach up to 100x, while the eyepiece has 10x magnification
16 times
There is a maximum of 20 times eyepiece. So with a 100x objective lens and a 20x eyepiece lens, the total magnification can reach 2000x. But this 2000 times is only a numerical increase, not a true amplification of 2000 times. For example, when the eyepiece is used at 10x, the objective lens is 100x, resulting in a total magnification of 1000x. This is because the actual magnification of the objective lens is still 100x, but the eyepiece has been changed from 10x to 20x. It looks 2000 times
1000 times, it's only a difference of 10 times.
