Into Unscientific

  Chapter 256 People are in Cambridge, waving their sleeves, attracting a dark cloud (Part 2)

   "?"

  Looking at Xu Yun with a mysterious face.

   Faraday subconsciously looked at his hand.

  I saw this moment.

  In the palm of Xu Yun's flattened palm, there was a transparent crystal.

   This crystal is about the size of a mint candy in a green arrow metal box, and has high light transmission.

  At this time, the crystal has been polished into a rectangular shape, with even ends and middle points, and looks somewhat similar to an **** plug.

  Faraday reached out and touched it a few times, realized the frosted feeling, and judged:

   "This is a crystal?"

  Xu Yun shook his head. Nine out of ten people would mistake it for a crystal when they saw it, and explained:

   "Mr. Faraday, this is the material I asked Dean William Whewell to prepare, called nonlinear optical crystals.

   "It can be used for frequency conversion of auxiliary light. We have prepared seven pieces in total. You will know the specific functions soon."

  Nonlinear optical crystals.

   This is a very common equipment in optical laboratories of later generations.

  Its purpose is similar to that of a grating. It can perform frequency conversion operations such as frequency doubling, sum frequency, and difference frequency on light.

  However, most of the nonlinear optical crystals of later generations are artificially designed and synthesized, and the development process is closely related to lasers.

   Such as lithium triborate crystal, lithium cesium triborate crystal and so on.

  The level of science and technology in 1850 was far from that level of technology, so Xu Yun chose to process natural crystals in a relatively primitive way.

   Fortunately, Cambridge University, as one of the top universities in the world in this era, has some reserves of rough crystals in the school.

   Get busy for hours.

  Laboratory tools People rushed out a few potassium dihydrogen phosphate crystals.

  However, no matter how primitive the nonlinear optical crystal is, the effect of frequency conversion is still much better than that of the prism, which is worthy of its difficulty.

  As for the role of nonlinear optical crystals.

   Naturally, it is for the next performance.

   Then Xu Yun handed over the nonlinear optical crystal to Lao Tang, and asked him to place and debug it according to his requirements.

  I thought for a moment, and said to Faraday:

   "Mr. Faraday, you are an expert in semiconductors, so you should know that the speed at which charges leave the metal plate is positively related to the voltage strength, right?"

   Xu Yun’s remarks may have some problems in expression in the eyes of later generations, but in 1850, when electrons had not been discovered, this description was very understandable.

   I saw Faraday nodded and said affirmatively:

   "Exactly."

  He discovered this phenomenon in 1833 when he was studying the chloride crystal cage compound, and tested the relevant results with an electric meter.

   Later, another JJ Thomson was able to discover electrons, which was also related to Lafarday's research manuscripts.

Of course.

  If you go back further, you have to go all the way to Cullen's generation, so I won't go into details here.

  Xu Yun further asked:

   "That is, the higher the voltage, the faster the charge will detach, right?"

   "Exactly."

  Xu Yunjian said that he snapped his fingers, and the vaccination was almost in place:

   "Then, Professor Faraday, what conditions do you think are related to the sparks that appear on the receiver in the photoelectric effect?"

   "Spark on receiver?"

  Faraday was taken aback for a moment, after a little thought, he blurted out a sentence:

   "Of course it's the intensity of the light."

  The corners of Xu Yun's mouth curled up slightly, and he asked:

   "So it has nothing to do with the frequency of the light, does it?"

  Faraday's tone was firmer this time, he shook his head decisively, and said:

   "Of course it doesn't matter, how could the frequency affect the generation of sparks?"

  The surrounding professors, including Stokes, also expressed their agreement:

   "Of course it has something to do with the light intensity."

   "Frequency? How does that thing hook up with sparks?"

   "There is no doubt that it must be the intensity of light, that is, the spark caused by the amplitude."

   "So does anyone want to see my wife's swimsuit?"

   In the eyes of Faraday and those professors.

   Although they still don't know why there is light on the generator, the receiver will have a synchronized spark.

   But it's obvious.

  The conditions for the appearance of sparks on the receiver must be related to the intensity of light.

   That is, the greater the intensity of the light, the stronger the spark will be.

  Because the wave in the classical theory is a uniformly distributed energy state, and the charge (electron) is something that is bound inside the object.

  If you want to play it out, you need to give enough energy to a single charge. (Electrons will be replaced by electric charge later, because the knowledge in 1850 is only electric charge)

  Analyze according to the theory of wave theory.

  Light waves will distribute energy evenly on many charges, that is, the charges continue to receive the energy of the wave and then jump out together.

   Waited until around 1895.

  The scientific community is also trying to explain this by adding the plane wave function and the Bloch function in the periodic potential field.

   Even in Xu Yunlai's 2022.

   Some scholars who have taken a different approach have also introduced the Born-Oppenheimer approximation in the scattering process of photons and electrons:

  They take the approximate first two terms in the actual calculation, and finally pass the wave function of the electron in the final state to obtain the photoelectric effect.

  However, it is quite amazing to not explain why the whole process is described by probability amplitude.

   In his previous life, when Xu Yun had a meal with a friend who was an external review editor of a certain journal, he heard that some people who held the above-mentioned concepts were forced to rush, and even said "you can succeed as long as you are lucky"

all in all.

  In the inherent concept of Faraday and others.

  Whether sparks can appear on the receiver must be positively correlated with the light intensity, and not half a penny related to the frequency.

  Xu Yun did not explain too much about this, but waited for Lao Tang to finish debugging the nonlinear optical crystal.

ten minutes later.

  Old Tang gestured to Xu Yun and said:

   "Luo Feng, the crystal has been fixed according to your request."

  Xu Yun thanked him, and greeted Faraday and others to come to Equipment Independence.

  At this time, the nonlinear optical crystal has been mounted on the refraction point of the reflective zinc plate, and can be rotated as needed at any time.

  Xu Yun first went to the side where the optical crystal was fixed, and made fine adjustments and calibrations according to the marks marked on it to make sure that the light could be refracted to the receiver smoothly.

   More than a minute later.

  Xu Yun stood up and said to Faraday:

   "Professor Faraday, the crystal has been debugged now, and everything in the circuit is normal."

   "The refracted light you see next will be orange light with a wavelength of 590 to 625X10-9 power meters."

  The wavelength of light was calculated by Thomas Young as early as 1807, but the unit of nanometer was not proposed by Chad Feynman until 1959.

   Therefore, the measurement description of the wavelength of light at this time is still expressed in negative several square meters of ten.

   In addition, all students who are not mad at the physics teacher should know it.

  The shorter the wavelength of light, the higher the frequency.

  Red, orange, yellow, green, blue, indigo, purple.

   Above from left to right, the wavelength gradually decreases, and the frequency increases in turn.

  Although Lafardie still couldn’t figure out why Xu Yun was obsessed with optical frequency, he still nodded in cooperation:

   "I remember, let's continue, student Luo Feng."

  Xu Yunjian said that he walked to the launcher again and pressed the start button.

   Whoosh—

  The voltage rises from zero again.

  1 Volt

  100 Volts

  300 Volts

  1000 Volts

  However, to the surprise of Faraday and others.

   When the voltage rose to the first 20,000 volts, sparks routinely occurred on the generator, but not on the receiver.

   Nothing happened.

   Soon, the voltage rises again.

  22,000 volts.

  23,000 volts.

   Well known.

  The intensity of light is related to power, and in the case of constant resistance, power is related to voltage.

   That is, p=u·u/R, the higher the voltage, the higher the power.

   However, when the voltage of the generator was increased to 28,000 volts, there was still no cremation at the receiver.

  Looking at Faraday and the others whose expressions gradually became serious, Xu Yun waved to Mai Mai again.

soon.

  Wheat came up with a convex lens.

   Friends who have been incarnated as Tiga should know it.

  Under normal circumstances, there are basically only three principles for increasing light intensity:

   Reduce the beam solid angle, reduce the spot size, or increase the energy of the light.

   Among them, the convex lens is the extended application of the first principle.

   That is, through refraction, the light is gathered finer, from scattered to condensed, so as to achieve the effect of increasing light intensity.

   Then Xu Yun took over the bald environment from Mai Mai, set it on a device similar to the stand of the later live broadcast, and moved it to the front of the reflector.

  Under the concentrating effect of the convex lens.

  The light from the electric spark splash on the generator was gathered into a small strip, and the magnitude was once again greatly improved.

  If it is converted into pure power, the magnitude of the splashed light at this time is about the same as the voltage effect of about 50,000 volts.

However.

  The reflecting plate is still empty like few students doing college physics problems.

  See this scenario.

  Lafarday, who originally thought that there would be no more accidents, couldn't help but feel a little unsteady.

  I saw him walking quickly to the side of the reflector, trying to check whether the optical crystal refracted the light to other directions.

  However, no matter how he calibrated the crystal, there was still no spark on the receiver.

But

  How is this possible?

  6 No less than 30 times, no matter how non-chief

  Uh, wait?

  Faraday suddenly thought of something, and glanced faintly at Tatum Austin in the crowd.

   Could it be because of this black classmate who clamored to grow watermelon and cotton?

   If I remember correctly.

  This black classmate is from Mozambique and is the next chief of the tribe, so he can receive a good basic education

   And just when Faraday's mind was fluttering.

   Xu Yun at the side guessed that the heat was almost ready, so he asked Mai to remove the convex lens.

   Turn off the power, and re-adjust the optical crystal.

  The target he chose this time was another natural cascade crystal with a walk-off angle of about 40°.

  As for the self-calibration, the stupid readers don’t know what it is anyway, because it is more unpredictable and time is limited, so Xu Yun didn’t go into the calculation.

  Anyway, under this experimental condition, the self-calibration performance should be above 80%.

  In short, what this crystal can reflect is blue light, that is, light with a wavelength between 440-485 nanometers.

  After debugging.

  Xu Yun returned to the side of the generator again and pressed the switch.

  The voltage is still rising from zero.

   After half a minute.

Snapped!

  A spark routinely appeared on the generator, and it was the .

  A spark appeared on the receiver!

  As the top physicists in the world, how could Faraday and others fail to realize what this means? !

   But this is not the end.

  Seeing Xu Yun beckoning again, Mai Mai walked up with a few polarizers with a grunt, and handed them to Xu Yun.

  Bumping the polarizer in his palm, Xu Yun's expression was slightly subtle.

   Speaking of the use of polarizers, many students must be familiar with it.

  It allows light to pass through a certain electric vector vibration direction, while absorbing light that vibrates perpendicular to it, that is, it has dichroism.

   That is dλ/λ=cosθdn/n.

   Among them, n is the refractive index with gradient change, which is due to the gradient change of flow field velocity between different media, n=1/√(1-u/c).

   In human terms, after natural light passes through the polarizer, the transmitted light basically becomes plane polarized light, and the light intensity is reduced by 1/2.

   Follow the historical trajectory.

  The polarizers commonly used in later laboratories would not be made by Rand across the sea until 1908.

   But in this dungeon, because the theory of volatility has not been suppressed for a long time like in the original timeline, it even surpassed the theory of particles.

   Therefore, many small devices related to the wave theory came out a lot earlier.

  According to the information learned by Xu Yun in "1650-1830: Two Hundred Years in the History of Science".

   42 years ago, in 1808.

   Not long after Marius verified the polarization of light, polarizers were first born.

  Although the polarizer at this time is far from being as fine as later generations, it can still support most of the experimental requirements in the early 19th century when the microscopic world has not yet been involved.

  It has always been used to support the wave theory of light—because only transverse waves can be polarized.

   But today.

   This little thing is in my hands, and it will become one of the tools to prove the particle theory

  Everything in the world is so magical sometimes.

  Xu Yun prepared a hybrid system composed of three polarizers this time. The polarization directions of the first and third polarizers are perpendicular to each other, and the polarization directions of the first and second polarizers are parallel to each other.

  At the same time, the second polarizer rotates around the direction of light propagation at a constant angular velocity w.

  Natural light becomes polarized light after passing through the polarizer P1, and the light intensity is I1=I/2.

  At the same time, according to Marius' law, the light intensity passing through P3 is I3=IcosΘ.

   Since the polarization direction of P and P3 is perpendicular.

  So the angle between the polarization directions of P and P2 is Φ=π/2-Θ, I=I(1-cos4wt)/16.

   Then according to Marius' law.

  I=IcosΦ=I3sinΘ=I(cosΘsinΘ)

  So the light intensity passing through P3 is =I(sin2Θ)/8=I(1–cos4Θ)/16.

  When cos4Θ=-1, the light intensity passing through the system is maximum.

   This system saves Xu Yun the trouble of manually reducing the light intensity. The calculation process is very simple and easy to understand.

   Then Xu Yun put the polarizer system in front of the zinc plate, took a deep breath, and returned to its original position.

soon.

  Under the effect of polarization combination.

  The intensity of the light splashed out of the generator has been reduced, and the period is as low as 1/16.

  But what made Faraday and others speechless was

  No matter how far the polarization combination is rotated, even if the light intensity is reduced by more than ten times, there will still be electric sparks on the receiver!

   Papa Papa.

  Looking at the jumping lightning in front of him, Faraday suddenly turned pale, let out a shah, covered his chest, and began to pant heavily.

   Stokes on the side was the first to notice his abnormality, and quickly supported his shoulders, his forehead was instantly covered with fine beads of sweat, and shouted:

   "Mr. Faraday, are you all right? Where is the school doctor? Where is the school doctor?"

  See this scenario.

  Xu Yun beside the generator was also trembling, and rushed to Faraday in one step:

   "Mr. Faraday! Mr. Faraday!"

  Until now, Xu Yun recalled one thing he had neglected:

  Faraday has a very serious coronary heart disease.

  On August 25, 1867, he died while reading a book in his study. A very mainstream view in later generations is that he had a sudden angina pectoris.

   More critically.

  Considering that the opening ceremony was full of people and the indoor temperature was not conducive to the storage of nitroglycerin, Xu Yun left the nitroglycerin in the dormitory instead of taking it with him.

   Right now, if such a master of science has an accident because of himself, he can really be said to be more guilty than Sun Xiaochuan.

   But what made Xu Yun's tense heartstrings loosen slightly.

  Faraday wrinkled his face and waved his hand at him first, and quickly took out a small bottle from his chest.

   Tremblingly, he poured out a tablet, stuffed it under his tongue, and swallowed it with his eyes closed.

   After a minute or so.

  Faraday's face gradually turned rosy, and his breathing returned to normal.

  He first glanced at Stokes:

   "Thank you, Professor Stokes, I'm fine."

   Then without waiting for Stokes to answer, he gently pushed away the support, walked quietly to the receiver, and stared at the clusters of short and dazzling sparks.

  The most powerful figure in the physics world at present, his eyes are unprecedentedly dignified at this time.

  The current situation clearly illustrates one thing:

   Within a certain frequency, the photoelectric effect has nothing to do with light intensity.

  As long as the light frequency is insufficient, it is useless to pull the light intensity to the sky.

  As long as a certain frequency is reached, even if the light intensity is small, the phenomenon will still occur normally.

   This is undoubtedly a situation that violates the existing scientific system, and the theory of light fluctuations cannot explain it at all.

  Because the wave theory describes that the energy of light is continuous, and the light intensity, that is, the greater the amplitude, the greater the light energy, and the energy of light has nothing to do with frequency.

  At the same time, when the receiver is irradiated with weak light, there should be an energy accumulation process on the generator, and no spark will be generated instantaneously.

   This is like a bullet train. If the flow of people at the entrance is not large, it means that the passengers have not yet arrived.

   According to the rules, the train must be full to start, so what can we do?

  The answer is naturally that we can only wait until all the people arrive before starting the car.

  But the current photoelectric effect phenomenon is equivalent to the train starting when only one or two passengers arrive.

  As for the particles.

  Faraday pondered for a moment, and soon thought of some explanation ideas:

  When a light particle irradiates a metal, its energy can be completely absorbed by a certain charge in the metal, and the kinetic energy of the charge increases immediately without accumulating energy.

  If the kinetic energy of the charge is large enough, it can overcome the attraction force inside the metal.

   Then it can leave the surface of the metal to form an electric spark

   But this way.

  Many theories based on the wave theory have doubts about their correctness.

  Even if we study it carefully, even the existing theory of particles is not really able to support the analysis of photoelectric phenomena.

  This is equivalent to the fact that the existing physical building has been dug out. Although it has not completely collapsed, it has already tilted.

  Think here.

   Faraday looked up at the night sky.

  At this time, the night sky is like a black curtain, only dotted with sporadic light spots.

   November 7, 1850.

  A Chinese person quietly appeared at Cambridge University.

  He waved his sleeves, and instead of attracting a ship of stars, he summoned a dark cloud.

  The electric sparks in the waves are rippling in everyone's hearts.

  The pool under the shade of elm trees is not a clear spring, but a mixed solution of silver chloride and fluosilicic acid.

  The summer insects are also silent because it is winter.

  Silence is Cambridge tonight.

   And actually.

  The shock brought by Xu Yun is far more than that simple.

   After all, as compensation for Faraday’s angina pectoris, it’s not too much to regret for him to fulfill his life, right?

   As for wheat.

   Sorry, I am a time traveler.

Note:

   Some students reported that the old law is easy to be regarded as a pharaoh, and I was also brought in. So I will call it Faraday in the future.

  (end of this chapter)