Scientists have hypothesized what propagation medium light depends on10

Ether. A virtual substance, assumed by scientists in order to explain the special properties of light, has many contradictory properties, such as the requirement that it is thin or even has no mass, is absolutely stationary, and is an elastic solid medium.

In the 19th century, the theory of ether was revived and developed, which began with optics, mainly as a result of the work of Thomas Young and Fresnel. Young explained Newton's rings with the interference of light waves, and in 1817, inspired by experiments, he proposed a new view that light waves are transverse waves, which solved the difficulty that wave theory could not explain the polarization phenomenon of light for a long time. Scientists have gradually discovered that light is a kind of wave, and most of the waves in life need a propagation medium (for example, the transmission of sound waves needs to rely on air, and the propagation of water waves requires the help of water, etc.).

Influenced by traditional mechanical ideas, they hypothesized that there was a substance called aether everywhere in the universe, and that it was this substance that played a role as a medium in the propagation of light. The aether hypothesis in fact represents the conventional wisdom that the propagation of electromagnetic waves requires an "absolutely stationary" frame of reference, and when the frame of reference changes, so does the speed of light.

However, according to Maxwell's equations, the propagation of electromagnetic waves does not require an "absolutely stationary" frame of reference, because both parameters in the equation are directionless scalars, so the speed of light is constant in any frame of reference.

From 1881 to 1884, Albert Michelson and Edward Morey conducted the famous Michelson-Morey experiment to measure the relative velocity of the Earth and the ether. The experimental results showed that there was no difference in the speed of light in different directions. This actually proves the principle of invariance of the speed of light, i.e. the speed of light in a vacuum has the same value in any frame of reference, regardless of the relative velocity of the frame of reference, and the ether does not actually exist.

Later, many experiments supported the above conclusions.

Albert Einstein boldly abandoned the aether theory, believing that the speed of light is the basic principle, and used this as one of the starting points to create the special theory of relativity. Although it turned out that the aether did not exist, the aether hypothesis still left traces in our lives, such as Ethernet.

Since sound was studied earlier than electromagnetic waves, it was initially thought that it was propagated by vibrations. Later, it was discovered that light could propagate in a vacuum, so it was slowly denied that it propagated by vibration. As for the medium, there is no certainty, because in life it is easy to find the answer.

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Light is an electromagnetic wave that can propagate independently of any one medium. Scientists initially thought it was propagated by vibrations.

Light has energy, according to the law of conservation of energy.

The energy is constantly being converted in one direction, so the light is constantly being converted into other matter, and there is a direction, which is the direction of the speed that we observe, and the conversion into other objects is what we call the need for medium propagation. Essentially it is the transformation of light into this medium, and this phenomenon is that light needs a medium to propagate. The definition of vacuum is controversial, but I will explain them one by one.

Vacuum is defined as the state of a gas in a given space that is below atmospheric pressure and is a physical phenomenon.

<> according to this definition, there is no air in the universe, so it is a vacuum. In Dirac.

The previous special theory of relativity.

In other physical theories, vacuum refers to the state of space in which no matter exists. What does that mean? The definition of vacuum is consistent with the concept of emptiness, which is meaningless in space.

According to this definition, if there is light and other undetected matter in the universe, then the universe is not empty. Since the definitions of vacuum and vacuum are consistent here, the universe is not a vacuum.

According to modern quantum field theory.

In physics, the vacuum is not empty, it contains a very rich physical content. The concept of vacuum with sub-standard atmospheric pressure.

The definition of vacuum is somewhat similar. The definition of vacuum is controversial, so let's look at the definition of emptiness first. Let's start with the definition of null. The definition of null is empty. Just like the Earth's surface and atmosphere.

Between what we think is empty, we call it space. But there is Changbu residual gas in the middle, and the air of the earth is always full of gas, so it is not empty.

The universe is filled with light and other temporarily invisible matter, so it is not empty. Essentially, nothing is empty. Therefore, nothing in the world is empty, and the perception of space is only the result of the error of the senses.

For example, water is always full of water, and fish think that water is empty, but we don't think so. The space between the Earth's surface and the atmosphere has always been filled with gas-resistant rolling bodies. We think it's empty, but when we look at it in space, we don't think so.

There is an axiom of space in mathematics: space is always infinite. Now there is no such thing as space, and the axiom of space comes from **?

What vacuum comes from? Therefore, both the mathematical definition of space and the physical definition of vacuum are created by people to understand the world, and there is no such thing as space.

Light does not need a medium to propagate, so it can burrow in a vacuum. The medium of propagation of light refers to substances such as air, water, glass, etc. In a vacuum, light relies on a special substance, a field, to determine the propagation of withering.

The propagation of light does not need a medium, because light is a wave-particle duality entity, and Gao Suimu has something called photons of its own. The photon is the carrier of light, the photon moves at the speed of light, and the light energy travels in a vacuum.

Because the propagation of light is not air, but a kind of particle molecule, which also exists in a vacuum, and there are many of them.

When light is refracted and the refracted ray, the incident ray, and the normal are in the same plane; The refracted and incident rays are located on either side of the normal, respectively; When the light is obliquely hit from the air into water or glass, the refracted ray is close to the normal, and the refractive angle is less than the incident angle, and when the incident angle increases, the refractive angle increases; When light hits the surface of water or glass perpendicularly, the direction of propagation in water and glass does not change; So the answer is: normal; Near; Small; Enlarge; Not changing

Answer: Light is refracted when it is emitted perpendicular from one medium to another.

Analysis: This is a special refraction phenomenon, when Snell proposed the law of refraction, he said that when the angle of incidence is 0, the angle of refraction is 0.

Light travels in different chambers of hollow media with different velocities. The velocity of light in water:; The velocity of light in the air:; The velocity of light in ice:.

Light always travels in a straight line in the same homogeneous medium; The speed at which light travels in a straight line in the same homogeneous medium is constant. When the two beams of light converge at the same point, the light energy at the point is simply added.

The laws of reflection and refraction of light. When light travels through the interface of two different media, some of them are anti-sensitive and some of them are refracted. Reflected rays follow the law of reflection, and refracted rays follow the law of refraction.

Light leaves the object and travels in the integrated field of the space around the object, in which case the propagation of light is determined only by the propagation medium where the light is located - the electric field (i.e., the ether field), that is, by the propagation medium - the direction and density of the electric field, and the speed of movement of the electric field.

On the earth, regardless of whether the static light source or the moving light source, the light emitted first propagates in the earth's space field, and in the process of light from other stars such as the sun propagating to the earth, the stellar light leaves the star first in the stellar field, then enters the galaxy space comprehensive field, and finally enters the earth's space field. It thus affects the propagation of light.

Therefore, the propagation medium of light is a comprehensive field formed by the interaction between the fields of various objects in space and the relative motion of objects. To put it simply, the medium of propagation of light is the field of objects that move with the objects.

The law of light propagation:

Light travels in a straight line at a certain speed in the same homogeneous medium;

When light encounters the interface between two media in the process of propagation, a part of the light is reverted back to the original medium, obeying the law of light reflection;

The other part of the light passes through the interface, changing the direction of propagation, obeying the law of refraction of light. The most accurate speed of light ever calculated is based on wavelength and frequency. In 1958, Froome found the exact value of the speed of light:

Kilometers and seconds. In 1972, Evenson measured the best value of the current speed of light in a vacuum: the meter second.

The speed of light refers to the speed at which light waves travel through a medium. The speed of light adopted by the resolution of the 15th International Conference on Weights and Measures in 1975 c 299792 458 0 001 km/s. This refers to the speed of propagation of light waves in a vacuum, because the medium has a great influence on the propagation speed of light, in transparent media with different refractive indexes, it is enough to divide the speed of light in a vacuum by the refractive index of the medium relative to the vacuum.

For example, assuming the refractive index of glass with respect to vacuum, the speed of light in glass = 299792 458 0 001 km/s

Kilometers and seconds. The refractive index is the ratio of the sine of the angle of incidence (the angle of intersection of the incident ray with the normal) to the sine of the angle of refraction (the angle at which the refracted ray crosses the normal) when light is emitted from one medium to another.

a. When light is obliquely emitted from one medium to another, the direction of propagation will change, and when it is perpendicularly incidentified, the direction of propagation does not change, so a is wrong;

b. When light is obliquely emitted into air from other media, the angle of refraction.

Greater than the angle of incidence.

Therefore, b is wrong and quickly pure;

c. When the light rays are obliquely reflected on the water surface, refraction and reflection occur at the same time, so C is wrong;

d. When light is emitted from one medium to another, the velocity must change, because the positive wave velocity is determined by the medium, so d is correct

Therefore, choose D

(1) Only when light is obliquely emitted from one medium into another, the direction of light propagation changes, so this question is wrong;

2) When light is obliquely emitted from air into other transparent media, the refractive angle is less than the incident angle, and vice versa, the refractive angle is greater than the incident angle, so this question is wrong;

3) Judging the correct optical path diagram of this question from the refraction law of light;

4) The reflection in water is formed by the imaging of a plane mirror, which is a reflection phenomenon of light, so this question is wrong;

So the answer is: ,