Do you know what color a mirror is? In fact, the mirrors we see are all green, isn't it strange? Sometimes we think of mirrors as silver because the back of the mirror is coated with mercury or aluminum. We sometimes feel that a mirror can represent any color, because you put a mirror against a blue wall, and it's blue. Let it face the red wall, that looks red, what you are facing, it is what color. This is because the mirror itself can reflect all the "light", and everyone here is in quotation marks.
This raises a problem, we usually say that the object that reflects all the light, it is white, such as this paper, it reflects all the light, so we say it is white. The substance that absorbs all the light is black, like a piece of coal. Why did the mirror reflect all the light, look not white, and image? When the paper now reflects all the light and must not be imaged, why is that? This is because although they both reflect all the light, but the way of reflection is different, because the surface of a piece of paper, you see at the microscopic level, it is potholed, so when the light is reflected, it will scatter the light in different directions, then this phenomenon is called diffuse reflection.
Although the white paper rarely absorbs the light that hits the surface, the diffuse reflection destroys the path of the original light, that is, the light becomes chaotic, and various different rays of light, mixed together, show white, so it cannot be imaged. Mirrors are different, the way mirrors reflect light is mirror reflection, this way of reflection can make the light that hits the surface of the mirror collectively deflect an angle, rather than scattering randomly. Therefore, the mirror can ensure that the light of the light source will not be chaotic, and the original structure will be maintained, so the mirror can perfectly present the image of an object.
Seeing this, we will think that the mirror is a relatively special white that reflects all the light. But things are far from simple, because there is no material in the world that can perfectly reflect electromagnetic waves, and he will definitely absorb more light of a certain wavelength, and then reflect some kind of light that he does not like. So scientists studied this problem in 2004 and published a paper.
Researchers also said that most of the ordinary mirrors are actually green, this hue is rarely felt, but there is a way to let us see the color of the mirror, now put the two mirrors facing each other, then it will form an infinite reflection of the mirror tunnel. If you study the electromagnetic spectrum reflected by mirror tunnels now, you will find that the wavelengths that mirrors easily reflect are between 495 and 570 nanometers. To the human eye, this wavelength of light is green. They found the same thing from the data measured by ordinary mirrors in the laboratory to their homes, so the picture above shows the reflectance of the mirror to the spectrum. It can be seen that mirrors are least fond of absorbing green light, so we think that mirrors are green.