An interesting historical fact is that Maxwell's formulation was composed of 20 equations in 20 variables which Heaviside showed could be reduced to just 4 equations in 4 variables. These are the ones taught today.

Very good vibes from this teacher, I don't know much English but I interpret technical questions perfectly. I am not a student, I am just a madman who invents things in the small laboratory at home and steals a little knowledge of the internet and the good people who provide it on the net. Thank you very much teacher.

All these lecture series are a gold mine, youtube is a more effective method of teaching than sitting in class ever will be. Simply because of the luxury of the rewind button... I wish the academic infrastructure acknowledged that fact and stopped throwing money away on poor lecturers (who might know what they're talking about but have such poor delivery skills). In the words of Feynman: "It’s impossible to learn very much by simply sitting in a lecture, or even by simply doing problems that are assigned." This is why I believe class time should be used strictly for questions and discussion... a two way road, not a one way force feed of information. The feeding of information can be done at home through tools such as KZfaq and amazing lecturers such as Walter Lewin who perfected the craft and put their heart and soul into it. As opposed to tenured professors who sit on their research and could care less about the students they need to teach, or the quality of their lectures.

Thank you for sharing your lectures with us. You're a great teacher Walter Lewin.

Walter, it's a shame there isn't a Nobel Prize for Teaching.

How is it possible for Lewin to make these esoteric, ridiculously difficult concepts understandable? Shame he retired - though he deserves it. He was a brilliant educator.

That was A Nice Lecture on Electromagnetic Waves Polarization, Professor Walter Lewin. The Math was a bit hard on me, but I began to see it in a spiritual Realm of Quantum Entanglement in the Cosmos of the Universe. This is the first time I have seen any of your lectures, Very Well Done. I look foreword to watching more of your videos, to learn about Electromagnetic Waves. I Like your style of teaching us this amazing subject. It was a lot of fun to watch, and learn, and see your demonstrations that you perform to your students, they had fun to. I like teachers like that, who can have fun, but, be serious at the same time of what he or she is trying to teach the class, that makes learning easier. That encourages students to want more. I also know this was an old Video that was uploaded back in 2015. To me it is a breath of fresh air of learning of a subject I did not understand when I was a young man back in the day. I hope you're still in good Health and still teaching your students. I have become one of them, at 68 years old. Which, go's to say, your never to old to learn. Thank You Professor. January 11th 2023. PSS, Check out Royal Raymond Rife's Discoveries, Back in the 1920's, I think you'll find it very enlightening.

These students have been so lucky to have attended your classes. And I still enjoy learning from your dynamic classes. They are just fantastic. Thank you, Professor Walter Lewin!

Dear Professor Lewin, At first, I would like to thank you for all the works you made available on KZfaq with your lessons. It's terrific. I learnt physics 30 years ago where I was quite successful, and for some reasons, I didn't make a career in Physics. Looking at the way you have done this marvellous job at the MIT, I am almost able to quit my job and everything, and to come back to the University, even to the MIT! Second, in your lecture #13 from MIT 8.03 video, you talk about the way that a human (you !) can see the polarized light and how to recognize it. Could you be kind enough to light my brain about this subject? Dear professor, thank you very much for what you have done in the way you did it, it is "extraordinaire". Best regards, Marc André. Paris, France.

we read electromagnetic waves today in class and im happy to have found this lecture here today~

Professor Lewen, you show such a deep understanding of the subject matter that goes beyond rote. You would be perfect for Africa! Thank you.

you have just opened my eyes...I am seeing what I was not able to see it before...Thank you professor..:)) Respect

Great lecture, conducted with briliancy and passion as well!

I wish I had this professor when doing this course... I had this guy (professor?) who was more interrested in research than to teach and made me hate this matter... Better than not failing the course, I would probably loved electromagnetism and been pretty good at it.

Mr Lewin, I’m a freshman at MIT right now taking this class, on this lecture. I love my professor but the way you teach, connect everything together, and give meaningful historical context, is simply inspiring. Thank you for uploading these to KZfaq

Had it about 40 years ago. Enjoy the lecture. Light bulb burning is something few can forget.

Excellent quality of presentations. I wish I was your student. Love from India.

Dear Sir Lewin, First I want to express my gratitude in sharing for free, those pieces of art that are your Physics Lectures. Your lessons helped me more than once in my engineering career and never stops to help: not just for understanding the argument, but also thanks to your teaching enthusiasm that is so contagious that my learning enthusiasm benefits. I can’t believe in my eyes when all your lectures disappeared from the Internet! Thanks for putting them online again. I’ve a little question: in 1:09:54 you said that you are able to teach a human to see a polarized light like a bee :) Will you ever do a lesson about this? I wish you all the best, Kind Regards. Paolo

i was struglling with college level physics. your lecture made it very easy

Dear Professor Lewin, I hope this finds you well. I am a senior in high school and absolutely love your lectures. I have been following your talks and KZfaq page for over a year now and, as it’s my last year of high school, have embarked on an ambitious task. I am endeavoring to reconstruct the electromagnetic wave transmitter/receiver demonstration you present at 1:00:07 in this video. I have exhaustively studied the theory and searched the far reaches of the internet and my school for answers on assembly methods, but have yet to find a satisfactory idea or construction methodology. I now turn to you for any guidance you have the time to give me. Any crumb of information would be greatly appreciated, I thank you for all you have taught me and all I have to learn from you. My best, -Henry

The representation at 26:12 is a classical representation of EM waves. But if the strength of the electric field is c (speed of light) times stronger than the magnetic field, and if the magnitude of the vectors in the representation represents the strength of the respective fields, does that mean that in a more "faithful" (though clearly unmanageable) representation the arrows used to represent the magnetic field should be c times shorter than the arrows used to represent the electric field?

interesting lecture. studied electronic engineering, work as cellular radio network engineer. Since GSM1800 in 1997, cellular antenna has used linear +45/-45 slant polarization as people hold cell phone in slant orienatation

I meant to go to bed 2 hours ago but I can't stop watching this. Thank you sir for keeping me loving physics. I was getting dragged down during physics 2 this past semester and these lectures have helped turn that feeling around.

This is one of the best lecture given by you amazingly super

I have seen some youtube lectures also from Yale. Like this it is extraordinary. Think about if only masterpieces like this will be used for lecture. It is meant globalisation of knowledge then. What ist local school then? Will they die? Thanks anyway to Walter for this passionating Lecture.

Excellent teaching , sir . Hats off !

Thanks for the lecture, this will supplement my two Maxwell's volumes to for a better understanding of the E and B fields.🎓📝📚📐

Great lecture! Thank you for your great uploads.

17:05 that phone call is written in the history of Physics Lectures by this great video

This video inspired me personally to do a demo E&M wave for my grade 12 students in Cambodia. Physics is magic and Beauty.

Sir your lectures give us real feel of physics Thankyou sooo much for these gems Just enjoyed your lecture🙏😊

I have thought about physical situations where there would be a pattern moving faster than the speed of light before I knew any concrete physics and now I understand I was thinking about phase velocity. It makes a lot of sense now!!!!!! I was so confused before because I thought that nothing could move faster than light.

Why is the antenna of the receiver longher than the transmitter, shouldn’t they be same to capture that specific wavelength?

Polarized vetor-rotation can be used for rotors of planes, to avoid birdstrikes perhaps, just a notion, thanks for lectures

I always like the physics and I'll thanks for this video :) sir

He draws a dotting line like the best one handed drum roll! He's second to none with hand speed, anyone disagree?

What happens to the oscillating magnetic field after light passes through a polarizer? Is it unaffected?

What about the long-known adverse biological effects of electromagnetic waves? A vital caveat to any lecture on this subject surely?

I always had a question when writing the expression for E field we took it along x direction and the wave in z direction. How do we know from the Maxwell's equation that E and B will be perpendicular and the wave will be travelling in the direction of E×B

why does the electric (or magnetic ) field vary spatially only with the direction of propagation of the wave (i.e. if the wave propagates in the "z" direction "E" is only a function of (z,t) ) ?

There is something I don't quite understand about EM waves: My professor told us that electromagnetic waves are caused by accelarating charges and the Wave can be understood as the 'information' of the changing electric and magnetic field traveling through space. How can we detect them over such long distances and why don't they lose intensity proportional to 1/r^2 ?

PERFECT. thank you sir, I'm really happy for this good job

WHAT IS NAME OF THE TRANSMITTER WHICH IS CONNECTED TO THE DIPOLE ANTENNA ? CAN ANYONE PLEASE TELL ?

At 1:03:26 the hand absorbed the electromagnetic radiation. That's very interesting. How does this happen? And, what wavelengths of radiation can the hand can pass through it? In General, if the electromagnetic wave hits an object, based on what characteristics of the object can we say if the radiation can go through it or not? And, lastly is this explained in any of the lectures?

Dear Prof. Lewin, at 42:20, the line you draw via the origin looks more perpendicular to the k vector, doesn't it? On this line, k = 0, because it is on the origin, then k dot r = 0 (not k perpendilular to r).

are there high res versions of these lectures that can be posted?

One of the beautiful things about this is how WL does not take any shortcuts with notation, which is helpful for viewers learning the subject. PS: "Don't even THINK of using a left handed coordinate system." Awesome performance.

His last words in this cracked me up. "Who wants a black eye? See you next Tuesday." Or, put another way, 'Who wants a black eye? C.U.Next.Tuesday.' Though I am sure this was an accident I still laughed like a drain.

Professor, when we write Maxwell's Equations in terms of line integral and surface integrals, we talk about E and B fields that penetrate through a surface. Or in other words, we think like- what will be the line integral of E along the edges of 'this' surface if 'that much' flux changes through the surface. But if we write the equations in terms of curls and divergence, we come to know how the E and B fields are related at every point in space. Am I correct ? Is it true that Maxwell's Equations in curl and divergence form describe these fields at every point in space but same Equations written in integral form can't do the same ? Thank you for teaching us with these amazing lectures

Hi sir, I have just finished watching your 8.02x course. In that course you derived integral form Maxwell equations. In this video you used differential form Maxwell equations. I want to know whether you have a video which explained differential form Maxwell equations in details?

At 1:07:30 why the average value of cos2(x) and not the integral of cos2(x) from 0 tο 2π?

this is an out of context question but sir would you please explain how the useful power of the AM wave lies in its side bands and not in the modulated carrier?

Sir, what is the way which you have learnt to tell wheather a light is linearly polarized? You refer to that at 1:09:50 into this 8.03, no 13 lecture. Please share I am keen!!

What a Masterclass

Sir I learned that we use electromagnetic waves to communicate wirelessly and electric field exist due to location of charge and magnetic field due to movement of charge. What I don't understand is that how can we communicate someone in free space ? According to web. there are about 10 atoms per cubic centi-meter. Doesn't that mean there are way less charge for E. and B. fields to do their thing therefore wave to propagate ? what did i miss or misunderstand ?

1:36 but isnt an electron and/or a proton a magnetic monopole? Im so fascinated with this subject matter, just trying to wrap my head around it. Awesome stuff

professor, how can humans recognise polarised light and the direction of polarization under ideal conditions?

Walter Lewin and H.C.Verma are legends who make you fall in love with physics

Thank you for this, Dr. Lewin. Very helpful. Please, if you would , explain to us how we know that the E field and the B field are in phase? I expected the peak/trough of the E field to align with the B field crossing through the zero line, and then the same with the E field crossing through zero where the B field was at a maximum/minimum. Could they not be out of phase by pi/2?

This is gold. Thank you for existing

At the end they did not applaud but they looked tired and uninterested , i find this incredible , one of the most enthused lecturer's i have ever seen on here , i wish i had such a teacher at my uni. I would have applauded ..to thank him

After viewing these wonderful lectures every student is going to enjoy physics more.

Hi professor Lewin. I love your videos. I am taking meticulous notes. Here's a question. What would be the wave function of the chalk when you make those dotted lines. It's obviously alternating stress and release of the the chalk with just the correct angle of the chalk. :-)

I just love you sir 😍😍😍😍😍😍😍 Love from India 🇮🇳🇮🇳

sir, at 38.03 minutes: as of my understanding. EM wave is moving in K- direction (because k- represents propagation direction), then what r- represents. i mean certainly wave is not moving in r- direction. wave is moving in k- direction. what way i can understand about r-direction?

I might get a few test questions right in his class if they are True/False or multiple guess... I mean choice.

Maxwell surely was a genius. I always preferred to remember them in their integral form. I remember you covered that in 8.02 Although, in the differential form, it's easier to see how a wave emerges. Had to pause the video to process the maths at times but I understand the subject much better now. Thank you. Amazing work.

Awesome teacher.

I have the impression that Maxwell's Laws serve a unique goal, and that is to give empty space all the properties of matter, except visibility and physical substance. In other words, it is the ether formulated mathematically.

As measured with clocksofc

Nice... Sir thanku so much 🙏🏻🙏🏻

This is wonderful

Good logical presentation.

Sir how much voltage was induced by receiver? and what kind of bulb should i use to demonstrate the existence of EM wave? I mean the wattage of bulb, rated voltage etc(12v or 24v etc). Tnx sir.

Sir, I have an idea and it's just a thought..so my question is; Can we create controled electromagnetic field to change the characteristics and behaviours of a specific area of earth in a certain moment so any incoming earthquake lose some amplitude ?

Sir if a capacitor connected to a battery and capacitor charged fully then what displacement current will be generates? ?

33:14 at this point you got my undivided attention. OMG

Sir , the length of wave in y direction /wavelength multiply by c , this equation I give to the chatgpt but it say it is "wrong ".

Don’t u usually subtract y term when computing determinant for cross product

At 48:58 from the geometry how come k/ky?

this has not subtitles :(

Professor, you calculated curl of curl of E and arrived at wave equation.This equation is derived from Maxwell's equations and is therefore valid for every time-dependent Electric Field in vacuum. Then the equation implies that it's solution must be a travelling wave. So does it mean that all time-dependent Electric or Magnetic fields that exist in vacuum must be travelling waves ?

Hello sir, if the electromagnetic wave is consists of two fields (electric field and magnetic field) that is perpendicular to each other, then why is the receiving antenna with a light bulb can't receive if it is in horizontal position opposite to the transmitter's antenna? (Is it only the electric field induced a current from the receiver and not the magnetic field?)

why crossed polarisers turn non polarized light into darkness????

A grand Salut to you Sir.

I love lewin sir

Professor, I have watched all the 8.02 lectures of you. I have a question- Maxwell's equation tells us that- closed loop line integral of B = u × ( conduction current + displacement current) through the surface formed by that closed loop . Let us think of an infinitely long wire that carries alternating current in vaccum. This will produce alternating magnetic field, thereby EM wave will be produced. But as we go further from the wire, the amplitudeude of B field should decrease because we move to a larger closed loop and the amplitude of both Currents do not change. This is contradictory to em wave where the amplitude of B field or E field cannot change !!!! It should not fall with increase in distance from the wire !!! Sir, please help me to understand what I'm missing.

Ty

Thank you, Professor, for making my life ambiguous😅.

Excellent Teacher🎉

Did anyone figure out how to differentiate polarized from unpolarized light and it's direction just with human eyes?

Professor Lewin, a question (if I may) @ 42:20 - " I draw another line perpendicular to r ". The line looks perpendicular to k rather than to r. Also, it's not clear to me why you chose to draw a line at this position. I'm struggling to grasp on the intuition behind this step and its subsequent results, i.e. k.r = 2pi, 4pi...etc. Any clarification would be very appreciated

I think the academic curriculum must be reframed to incorporate these online lectures.

Sir pls enable caption for this video

About polarization, does the magnetic field induce unpolarized electric field, after its been polarized? Because the polarizer only polarizes the electric field, so there're still magnetic field that isn't polarized, right?

professor, how did you built that antenna. I wanted to build one by myself. if you have any paper/document that exactly makes it, sir please do share. I am a student of Electronics and communication (Bachelors) than a student of Aerospace (AVDC- Cranfield University). thankfully your old student who is admiring and seeing your lectures from 4 years.

what a great lecture ! Thank you very much.

How electromagnetic waves are actually in air..... What happens in the air when so called "wave" travels.... I know the equation stuff but i want to know what happens in the air... Thank you!

Sir 53:18, when u said theta goes to 0 Lx becomes infinite.. can u specify why it happens in bit more detail? as i didnt catch it with what u said in the lecture sir.... please sir.....

Fun fact about the lecture: this was filmed 17 years ago