Radio: the application of electromagnetic radiation

      Last time, we talk to the part that Hertz observed the electromagnetic radiation and made a conclusion that light is a kind of electromagnetic radiation. Although Hertz is the first man who observed electromagnetic radiation, he didn't concentrate on the application on electromagnetic radiation. Hertz even said that "It's of no use whatsoever, this is just an experiment that proves Maestro Maxwell was right." Now, radio is using all over the world, it's because two man who devoted in developed the wireless communication.

Guglielmo Marconi

(https://upload.wikimedia.org/wikipedia/commons/thumb/0/0d/Guglielmo_Marconi.jpg/220px-Guglielmo_Marconi.jpg)

      A.D.1864, Guglielmo Marconi transported the electromagnetic radiation in the distance of few centimeter. 1896, Marconi got the patent right of radio in England. After a year, Marconi founded a company of radio transmission, it will become the famous company "Marconi Company" in future.

Nikola Tesla

(https://upload.wikimedia.org/wikipedia/commons/thumb/d/d4/N.Tesla.JPG/220px-N.Tesla.JPG)

      A.D.1893, Nikola Tesla displayed wireless communication to public. 7 years later, Tesla got the patent right of radio in USA. However, USA cancelled the patent right of Tesla and gave it to Marconi in 1904. Nikola Tesla pasted away with the sorrow about radio's patent right in January 7, 1943.

Nicola Tesla's patent right of radio transmission

(https://i1.read01.com/image.php?url=0CzhHO0B)

June 21, 1943, USA gave the patent right of radio back to Tesla. But some scholar think the reason is not because USA really think Tesla is the first man who create wireless communication, the truth is USA didn't want to pay the huge amount of money to Marconi Company because of using radio during WW1.

      By the way, Guglielmo Marconi got the Nobel Prize in Physic in 1909.

Light is absolutely WAVE

       A.D.1865, James Clerk Maxwell announced a equation set of electromagnetism called Maxwell's equation. Most of us knows that Maxwell's equation combined electrical science and Magnetostatics together with 4 equations. But the equation set that Maxwell announced at 1865 has 20 equations in the set, not as which high school text book says. With the equation set, Maxwell predict that light is a kind of wave and precisely Electromagnetic radiation (EM radiation or EMR).

       James Clerk Maxwell

(https://upload.wikimedia.org/wikipedia/commons/5/57/James_Clerk_Maxwell.png)

22 years later, Hertz was addicted with the instruments in a lab at Karlsruhe Germany. He's going to make a incredible experiment that has be called as one of the most important experiment in physic. With the experiment, Hertz observed the Electromagnetic radiation by his own eyes!! Observe EMR was already a inspiring achievement but there's still more discover. With the information this experiment showed, Hertz calculated the speed of EMR and the speed is absolutely 300 thousand km per second (the speed of light).

       Heinrich Rudolf Hertz

(https://upload.wikimedia.org/wikipedia/commons/5/50/Heinrich_Rudolf_Hertz.jpg)

With the result of Hertz's experiment, the war of light is particle or wave took a bow. Through hundreds of year, wave group knocked down the particle group and with the theory Newton and Maxwell gave physic reached a successful realm.

 Hertz's experiment

(http://pic.pimg.tw/zitolife/1401206733-3362421011_l.jpg)

Light is not PARTICLE !!

     Last time, we talk to the part that public usually agreed the opinion of Newton. But, nowadays we know light shouldn’t regarded as particles. There must be someone who confirmed that light wasn’t particle, and the first guy we will talk about is “Thomas Young”.

 Thomas Young

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     Thomas Young born at Milverton England and he is a real real real genius. He could speak 10 language when he was only 16, studied medical science when his 19. Although Young was so incredible in different field, we concern on the contribution on physic. When Young was 34 he published a book, in his book there’s a famous experiment “Double-slit experiment”. This experiment trivially showed that light shouldn’t be a kind of particle.But there’s still something wrong with the wave theory.

Double Interference Experiment

(https://en.wikipedia.org/wiki/Double-slit_experiment)

     Augustin Fresnel, engineer from France, gave out a paper of the solve of light diffraction problems using mathematical inference. With the model Fresnel gave there should exist a spot in the middle of the shadow, if we place a light bulb in front of a plat. It sound impossible in the past (it sound quite strange in recent too), but experiment showed that it really pop out a spot!!!!The spot is called Arago spot. There is a misunderstanding about Arago spot, but I’m not going to talk about it.

 Augustin Fresnel

(http://www.sabix.org/bulletin/b37/fresnel.jpg)

     With the events above it’s almost sure that light is a kind of wave, but there’s still some important men we should know, for example “James Clerk Maxwell”.