Into Unscientific

The speed of electromagnetic waves is similar to the speed of light.

Following the words of wheat.

Faraday was taken aback for a moment, and immediately slapped his forehead suddenly, sending out a crisp "snap".

I see

No wonder I feel this number is somewhat familiar.

2.97969X10^8m/s, isn't this almost the same as the previously calculated light speed? !

But

Why is this so?

To know.

In the current era, the scientific community has a relatively clear understanding of mechanical waves:

It is the transfer of momentum and energy in matter caused by the propagation of disturbances.

At the same time, mechanical waves can be divided into two types: longitudinal waves and transverse waves.

For example, waves along strings and sound waves, etc., and of course mixed waves.

In addition to the different types of waves, the speed of propagation is also different from wave to wave.

For example, the speed of sound waves is 340 meters per second. The person who measured this value is called Durham, an Englishman.

In 1708, he observed the cannon with the naked eye and measured that the speed of sound was about 343 meters per second at 20 degrees Celsius.

As for the speed of sound in water, it was Collaton.

He was in Geneva—the Geneva Ha of the place name. Through a small precise experiment on Lake Geneva, he calculated the speed of sound in water to be 1435 m/s.

In addition, there are sine waves and even light waves. There are already measurement methods and results for these values.

According to Faraday.

Electromagnetic waves originate from electric and magnetic fields, and the oscillation frequency of the electric field is inherently at a high level.

Coupled with the comparison of phenomena, the wave velocity of electromagnetic waves is naturally unlikely to be a low value.

But this "unlikely to be a low value" means that the sky is tens of kilometers per second, which is faster than the seismic wave speed guessed by John Michel in 1760.

But according to the measured results, the speed of electromagnetic waves is actually close to the speed of light?

From the perspective of Faraday or every boss present, he can realize what this similarity represents.

Coincidences of this magnitude basically do not exist in physics, and some substances with similar key values ​​on ultra-high scales must have a certain relationship with each other.

Seeing that Faraday was silent, Joule on the side hesitated for a moment and asked:

"Student Luo Feng, could it be that we made an error in the measurement process?"

Xu Yun glanced at him.

As a descendant, Xu Yun can somewhat understand Joule's thoughts.

In the face of phenomena that can impact one's three views, it is normal to have doubts in one's heart.

Xu Yun shook his head lightly and explained:

"Mr. Joule, you have also seen the inspection session just now. We have collected no less than 50 sets of pitch data."

"Although there may still be deviations in the values ​​calculated from this, such deviations will at most lead to differences in a few decimal places, and the concept of 'magnitude' is still very accurate."

"The other thing is."

While talking, Xu Yun dug out the earliest classic wave equation from the table, pointed to the equation and continued:

"We can actually start with the wave equation and calculate the speed of electromagnetic waves from a purely mathematical perspective."

When Faraday and the others heard this, they quickly turned their attention to the equation.

A few seconds passed.

Newman, who had never played much, suddenly snapped his fingers and drew a circle on μ0ε0 with a pen:

"That's right, we can invert the wave velocity from the perspective of the equation, oops, I should have thought of this earlier!"

mentioned earlier.

The wave equation of the electric field is ▽B=μ0ε0(B/t).

The wave equation of the magnetic field is ▽E=μ0ε0(E/t).

Compare the wave equations for electric and magnetic fields, and you'll see that they have exactly the same form—just swapping E and B.

This shows that the waves existing in the two are completely consistent in velocity. At the same time, comparing the velocity term of the classical wave equation, it is not difficult to find another situation:

The speed of electromagnetic wave can be deduced from the wave equation of electromagnetic field.

That is.

V=1/√￣μ0ε0.

Among them, μ0 is the absolute permittivity, and its value is 4π×10^-7m·kg/C.

ε0 is the vacuum dielectric constant, with a value of 8.854187818×10^-12Cs/kg m.

The unit of the former can be written as N/A, and the latter can be expressed as F/m.

Just follow normal history.

Whether it is Farah or Ampere.

These units were not formally defined until the International Electrotechnical Congress in 1881.

But the same curl as before.

The scientific community in 1850 had already recognized this concept, but the expression form was still Cs/kg·m for the time being.

Just like the unit of capacitance, coulomb, it was also a value defined at the International Electrical Congress in 1881, but it had been used badly before that.

The reason why such a meeting was held in 1881 was mainly because the American and Asian countries did not have a complete system in this regard, so such a formal meeting was used to characterize the unit.

Among them, Asian countries mainly refer to neon, which is related to the Meiji Restoration, so I won’t go into details here.

Incidentally.

Seven electrical units of measurement were defined at that meeting, namely:

Coulomb, Ampere, Volt, Ohm, Farah, Henry and Siemens.

Of course.

Seeing this, some students may ask:

With the level of technology in 1850, how did you calculate those data in a vacuum?

This is actually somewhat similar to when Xu Yun was writing novels in his previous life, a reader asked, "Can the value in 1850 be so accurate?"

The root cause of these two problems lies in the inherent cognitive barriers-many people think that 1850 and the present are two eras, and it is great to be able to calculate 10x10=100.

This is actually a very serious mistake.

Actually.

1850 can be regarded as the approaching node of modern science.

Within this node, many fields are not as primitive as everyone thinks.

For example vacuum measurement.

In fact, as early as 1643, Galileo's student Torricelli made the world's first device to measure gas pressure.

He confirmed by experiments that the atmospheric pressure is equivalent to the pressure of 760mm Hg. That is, 7.6×104Pa, which created a precedent for quantitative measurement of the degree of vacuum.

Before 1850, Borden—that is, the big guy who tinkered with the Bourdon tube, even invented the deformation vacuum gauge.

Otherwise, why do you think wheat can calculate the speed of light in a vacuum in Maxwell's equations?

There are insurmountable barriers between 1850 and 2022, there is no question about that.

But this does not mean that that era was a pure primitive society without any bright spots.

This is the same as today's online novels. In 2022, there will be more than one book with an average subscription of 100,000. This is something that was unimaginable in 2012-at that time, the average subscription of the head was only more than 10,000. Twenty thousand is all.

But can you say that the online works in 2012 have no bright spots?

Obviously not.

Works such as "Covering the Sky", "Swallowing", "Eternal Life" and "Mortal Man" are still classics even if viewed from the perspective of 2022.

Each era has its own limitations, but it also has its shining points.

The line of sight returns to reality.

Thinking of V=1/√￣μ0ε0, then the next step is very simple.

"V=1/√￣4π×10^-7m kg/CX8.854187818×10^-12Cs/kg m"

Such a complicated calculation process was naturally handed over to Wheat again:

"So V=√￣8.987552x10^16m/s"

"The final answer is 2.9979X10^8m/s!"

The value calculated by Wheat is the speed of light in a vacuum. In addition, there are some errors in the measurements by Xu Yun and others, so it is very normal that there are some differences after the decimal point.

"2.9979X10^8m/s"

Faraday repeated this number, and at the same time he was filled with emotion, another idea popped up out of nowhere:

If I want to teach at Cambridge University for a long time, I guess I have to ask Prince Albert for some nitroglycerin regularly

Then he took a deep breath, looked at Xu Yun, and asked:

"Student Luo Feng, from this point of view, isn't light and electromagnetic waves the same thing?"

Xu Yun nodded resolutely, and was about to say something, but stopped abruptly when he was about to say it.

In an instant.

Many thoughts raced through his mind.

He hesitated for a moment, and what should have been said was replaced by another sentence:

"Yes, Mr. Faraday, he finally came to a conclusion based on the research done by the ancestor of the fat fish."

"That's electromagnetic waves, light of a special frequency."

Friends who have studied physics in the second year of high school should know it.

Light is actually a kind of electromagnetic wave, which belongs to the proper subset of electromagnetic waves.

In layman's terms, it is a certain frequency. That is, electromagnetic waves within the wavelength range, we call it light.

For example, human beings are only a part of primates. If human beings are compared to light, then electromagnetic waves are all primates.

Of course.

These are just some basic concepts, and it will be very complicated if you go deeper.

For example, electromagnetic waves can be said to propagate without a medium, or through space-time as the medium. For example, space-time fluctuations are open strings in string theory.

Therefore, the curvature of space-time caused by gravity can affect light, and some people even think that the ether that people have been looking for is actually space-time itself, etc.

Especially some folk science, love to put forward some weird opinions in this regard.

It is said that someone sent an email to the Academy of Sciences last year, expressing their hope to enter the tokamak for observation.

Others can die in the morning after hearing the Tao, but this one can die in seconds after hearing the Tao.

all in all.

Regardless of which of the deeper theories is correct, the notion that light is a proper subset of electromagnetic waves is fine.

But after thinking about it again and again, Xu Yun decided to put forward a contrary statement:

Electromagnetic waves are a type of light.

After all, as far as the current situation is concerned, the character design of 'Fat Fish' is a bit too perfect.

Numerous examples in history tell us that a perfect "God" does not exist and problems may arise.

Anyone will make mistakes, and even have black spots that are criticized by others.

In the long run, this is not a good thing.

So Xu Yun simply imitated Xiao He's self-defilement and put a black halo on 'Fat Fish'.

In fact, Xu Yun had considered this issue before.

Naihe wanted to find an experimental target that could be used as a black spot, but at the same time had little impact on the development of the history of science. It was really difficult to screen.

And coincidentally, electromagnetic waves are a very good choice.

The dispute over the properties of electromagnetic waves and light has always been maintained in the theoretical field, and what should be done in the practical link.

Even if you say that light and electromagnetic waves are another non-existent thing—for example, they are both called "fishing girls", it will not have much impact on the actual operation.

At the same time in the past few years.

When JJ Thomson discovered cathode rays from experiments, most of the scientific community will doubt Xu Yun's statement.

Once the truth about electromagnetic waves is discovered, many people will be relieved:

Oh, it turns out that Mr. Fat Fish also makes mistakes.

pattern.jpg.

Of course.

At this time, Faraday didn't know what Xu Yun was thinking.

After hearing Xu Yun's words, a slight sense of strangeness flashed through his heart, and he quickly accepted the explanation.

After all, judging from the current phenomena, there is really no obvious difference between light and electromagnetic waves.

Later, Xu Yun and Faraday and others verified the characteristics of electromagnetic waves with equipment such as polarizers, and found that it also has the characteristics of refraction, reflection, and polarization.

At this point, all that remains is the finishing touches.

Faraday took out a piece of parchment and wrote the final conclusion on it:

[It has been verified that electromagnetic waves are a special kind of light].

Then Faraday and others summarized the experimental results again, and planned to officially announce the relevant content at the next academic conference.

so far.

Xu Yun's first wave of coquettish operations at Cambridge University was officially put to rest.

I think from now on, I won't encounter anything more exciting than this

Bar?

Both Faraday and Joule Kirchhoff came out, Xu Yun really couldn't think of anything bigger than this battle.

Well, absolutely impossible!

If there is, he is willing to eat that ax on the spot!

half an hour later.

After packing up the equipment, Xu Yun returned to dormitory 302 with Mai Mai.

Just entered the house.

Xu Yun untied the scarf and lay on his back on the bed.

be honest.

The two-day experiment seemed to be going very smoothly, but for Xu Yun, the pressure on his shoulders was really heavy.

After all, even if there is a mistake in one detail in the whole process, it may have an irreversible impact on the result.

Fortunately, relying on the character that I had diligently updated and accumulated in my previous life, I passed this hurdle smoothly.

And just as Xu Yun was lying on his back.

A long-lost light curtain appeared in front of him.

[It is detected that the first ring task of the Wallfacer has been completed, the task evaluation and the second ring task are being generated]