8.02x - Lect 16 - Electromagnetic Induction, Faraday's Law, Lenz Law, SUPER DEMO
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- เผยแพร่เมื่อ 21 ก.ย. 2024
- Electromagnetic Induction, Faraday's Law, Lenz Law, Complete Breakdown of Intuition, Non-Conservative Fields. Our economy runs on Faraday's Law!
Lecture Notes, Non-conservative Fields - Do Not Trust Your Intuition: freepdfhosting....
THIS LECTURE IS A MUST - Read the Lecture Notes of this Lecture.
Assignments Lecture 13, 14, 15 and 16: freepdfhosting....
Solutions Lecture 13, 14, 15 and 16: freepdfhosting....
![[TH] JFT vs RLF - VCT Ascension Pacific - Day 2](http://i.ytimg.com/vi/PuIH7w_jO6c/mqdefault.jpg)
For those that keep saying that you wished he was your teacher when you were younger or whatnot: look at the bright side, that it is possible that he is now a teacher to everybody is a beautiful thing. It's a wonderful time to be alive.
But you can be that teacher as well 😉
Lmaoo 😂😂
Absolutely! I cry with pure joy watching his passion scream through his lectures!
THATS GREAT PRIVLEGE WE ARE
ENJOYING.
He is also a very sexy man
This website contains all my 94 course lectures (8.01, 8.02 and 8.03) with improved resolution. They also include all my homework problem sets, my exams and the solutions. Also included are lecture notes and 143 short videos in which I discuss basic problems.
ENJOY!
+shreyas Sudhaman I learned it correctly at my University in Delft. The Netherlands. In addition there is the FAMOUS book by Jackson. It's the "bible" of electrodynamics. No mistakes in Jackson. It's a shame that so many college books have it wrong. It shows that many physics teachers do not understand Faraday's Law. FL makes our economy run!
+Lectures by Walter Lewin. They will make you ♥ Physics. www.amazon.com/s/ref=nb_sb_ss_i_8_8?url=search-alias%3Dstripbooks&field-keywords=jackson+electrodynamics&sprefix=Jackson+%2Cstripbooks%2C163&rh=n%3A283155%2Ck%3Ajackson+electrodynamics
+shreyas Sudhaman
They were offended and argued that their way of explaining was sound and led to the correct answer. I agree that they got the correct answer but the method they used was blatantly wrong. a+b=-c. c is NOT zero. a+b+c=0 . They then state that Kirchhoff's rule demands that a+b+c=0 which is WRONG. a+b is the closed loop integral of E.dl and that is -c (-dphi/dt) and that is NOT zero. If K's loop rule could be used, then
the closed loop integral of E.dl (thus a+b) must be zero. But it is NOT zero.
+shreyas Sudhaman It's probably wrong in text books for 2 reasons. 1. There are many physics teachers who do NOT understand FL. 2. They have a religious believe in Kirchhoff. They think that is easier for students to understand. They never write down that the closed loop integral in an RLC circuit (my lecture 20) is -dphi/dt. thus -L(dI/dt). They bring this term to the left of the equation; the eq then becomes zero. They then argue that this is consistent with Kirchhoff. That is blatantly wrong. I suggest you read my lecture notes of lect #20.
+Lectures by Walter Lewin. They will make you ♥ Physics.
Well, they sometimes teach the Kirchhoff's second rule as "the sum of all emfs in any closed loop is equivalent to the sum of all potential drops in the same loop". I.e. ohmic voltage grop (IR) in the closed circuid is equal to the electromotive force induced in the circuit. Could this definition help to reconcile non-believers with reality?
Any class 12 indian students here🖐️🖐️
Yep
Look, where I have ended up 😓
Hlo 😅❤
Me 10th
Me 9th
I teach Electromagnetic Theory in University and every time before I teach Faraday's law I go through this lecture as a part of my preparation, it is so so good.
Which University sir
At comsats atd.. am your student sir❣️☺️
PKMKB is an acronym for, 'P@kist@n Ki Maa Ka Bh*sd@'. It is an abusive phrase used to describe the aggression and hatred towards terrorism and Pakistan. In this context, the word PKMKB is used to propagate the collective boycott of Pakistan and the fact that it supports terrorism.
It sure is Sandeep, he is spectacular with his lectures.
This is gold.
I'm over here getting an MIT education without the cost of tuition... love it.
Where is This MIT
@@shreyas.k898 Massachusetts
@@shreyas.k898 Cambridge, Massachusetts
Same here while I’m studying science 10 I’m in advanced science physics cool
In INDIA , we study these things even before high school.
I can see why MIT are keeping chalkboards as opposed to replacing with hi tech. Your chalk skills are amazing. Great lecture too! Thank you.
Sentenced
🙂
Chalk > SmartBoards
I'm from Brazil and I better understand you than my professors, it's crazy because I've been learning English for 2 years! I wish you a long and happy live. God bless you
That's great!
Hello once again Dr. Lewin;
Your lectures are proving to be a fun and productive learning experience for me.
Your passion for physics, your knack for communicating and educating, and the strength of your convictions in the wake of the controversy created surrounding the validity of Kirchoff's Loop Rule, have inspired me to challenge my own understanding of concepts that I've often failed to appreciate. I credit you for empowering and inspiring me to treat both sides of the controversy equally and fairly. It's amazing how so many have attempted to set the record straight and discredit your provocative claim by simply declaring that you are wrong; and then proceed to apply their own spin to the results of your experiment, defending Kirchoff's Loop Rule, and focusing only on your error; while adding nothing toward understanding of the concept of Faraday's law that you were presenting.
All of the arguments I've reviewed and studied are convincing enough at describing what we were all taught; but none seem to convey an understanding of your point of view or your presentation, sufficient enough to challenge them. I wasn't looking to be told what I know... or think I know. I was intrigued by the possibility of learning something new. I began dissecting your lecture, hanging on every statement and visual aid presented until I became certain that I understood you every step of the way.
At 38:36 in your lecture, you make the statement "So far so good!", and I am in complete agreement with you up to that point, including your corrected Ohms Law equation (at 35:59) up through and including your statement at 40:28 "... and now it's not so simple... because there's no battery." This is where you switch from a conservative model to a non-conservative model, at which point the difference between them becomes quite clear and intuitive.
Aside from correcting your Ohm's law error, you never discovered nor took note of it through to the end of your lecture. I'm speculating that the error may have been steering your thinking in the moment and stayed with you; but maybe not.
Continuing from 40:28, you follow with "and so now when I go from point D to point A... I don't have the "1" and therefore I now find -0.1 Volts... I find a totally different answer."
This is where I became disconnected, and asked myself the question "How can the voltage drop across two resistors be opposite in sign when the current is flowing in only one direction? So I listened further for the answer... As you stated... this is not intuitive.
At 44:20 you make the point: "keep in mind that with non-conservative fields, it depends on the path". That statement seems intuitive and clear to me, and I interpret this as the encircling path of the loop with the induced emf flowing in one direction only at all points around the loop; but changing direction in concert with the building and collapsing of the magnetic field that induces the emf in the loop; as observed in your multi-turn loop demonstration using a solenoid and center reading Galvanometer.
In the schematic drawing shown in your lecture notes, you correctly show the loop current flowing clockwise inside the loop, with current flow from node D flowing down through R2 and down through voltmeter V2 to node A.
On the opposite side of the loop, you correctly show the current flowing up from node A through R1, and up through voltmeter V1 to node D.
Missing in your drawing is the polarity of the connected voltmeters. Your schematic is accurate and clearly indicates that the the polarity of the voltmeters, and the voltage drops across R2 and R1 are reversed; as they should be when diametrically opposite the loop from each other with current always flowing around the loop in the same direction. Therefore experimental measurements must observe this convention; with the positive side of voltmeter V2 connected to point D, and the positive side of V1 connected to point A.
Assigning the the polarity of the voltmeters, consistent with the convention used in your schematic will show that V1 = + 0.1V, and V2 = +0.9V, with their sum now equal to the 1.0V induced emf in the loop. Your experiment demonstrates and satisfies all of the supporting findings of Oersted, Faraday, Kirchoff, Lenz, and Ohm without conflict. Additionally, it also demonstrates that the validity of Kirchoff's Loop Rule is independent of conservative and non-conservative fields.
A slight rearrangment of how the loop is presented, may also make it a bit more intuitive to conceptualize. Unfortunately; I am unable to upload my rearranged schematic drawing to TH-cam.
Best wishes and respectful regards;
Gary O'Neil
Gary I am sorry that you still do not understand this. Do not feel bad, you are not alone; non-conservative fields are not intuitive. Yet they run our entire ecnomy. All the best!
i m studying medicine. I left learning physics 3 years ago. But here i m watching him lecturing for hours. truly genius
Helo. HMU for medical papers, I will help handling them effectively
Prof Lewin. Your lectures are among the best science lectures ever delivered anywhere. The MIT students were incredibly lucky that they got it live,but thanks to the marvel of the internet, practically anyone anywhere in the world (provided they understand English) can learn from your incredible ability to teach. My deepest respect for you and a deep bow of gratitude.
thank you!
Mr. Lewin, I am an automotive technician, and teach small groups of other technicians, I use Faraday, and Ohms law math daily in my instruction, during the course of me teaching ignition coil(step up transformer) analysis, and failure. I use a bench test setup with a simple circuit, a 13.8 vDC regulated supply, a ground side switch and a commercially produced, internally resisted, automotive grade ignition coil wired to a .050 inch air gap.
I never understood why my switch would burn up only upon the opening of the circuit, realizing the effects of Faradays law and the internal structure of the step up transformer used, I added a capacitor(in the automotive world they are labeled as condensers) in parallel with my switch to absorb the left over current during the collapse of the magnetic field. This resolved my issue, and I figured it out thanks to this video, I watched it for the first time yesterday. and this was the first of your videos I have ever read, but it will NOT BE THE LAST!
I want to thank you for allowing this information to be available to those of us that were not placed in a position to learn it before.
thank you for your kind words. This lecture is THE MOST important but also THE MOST difficult of my Electricity and Magnetism MIT course. I demonstrate that 2 identical voltmeters connected to the same 2 points in a circuit read very different values, the polarities are even reversed. Few people under stand (or accept) the fact that when there is an induced emf that potential difference (defined as the integral of E dot dL) is not determined. It depends on the path and you can can values that differ by a factor of 100 and more.
No! It completely makes sense the way that you explained it, the ∫ E . dl can not be determined. I have my own challenge explaining that the simple formula of Ohms law that is used in the automotive industry, is not correct in that we measure circuits during inductance, where all the real world variables of heat and voltage drops across the connections of the circuit MUST be accounted for. Although not nearly as complex as your teachings, I understand, and share your passion for physics.
I meet with technical college instructors, they teach students that if they measure the resistance of the solenoid, and open circuit voltage my math should translate in the real world to the current in the circuit. It simply does not work in the real world.
@Keith Perkins ... later on I am sure he will cover the more intense circuit calculations where you trace down all the voltages currents resistors and capacitors physical and imaginary ... this is EXACTLY the lesson you want to find and watch atm the name of the method escapes me as last time I worked with it was about 30 years ago
.
Perhaps Prof Lewin can add it the circuit analysis I'm thinking of ... the one with the fun complex numbers ;)
@@lecturesbywalterlewin.they9259 If the voltmeters are both connected to the same points, how do you know which path each will read? Couldn't they both read the left path at the same time or read the right path at the same time? Wouldn't that give your two path demonstration only a 50% chance of each reading the other path?
I applied Maxwell's eqs to the circuit. That dictates the currents that go through the voltmeters and that results in their reading.
Try this video
th-cam.com/video/wz_GqO-Urk4/w-d-xo.html
Wow, I teach electro tech to apprentice electricians, and I found this lecture to be fantastic.I thought for a moment that it was going to get too complicated, but no ,just the opposite. I understood all that was being taught, and while beyond the scope of what I need to teach, this additional knowledge has help me considerably.
How lucky we are to have the brilliant teachings available, and I have not have had to pay university fees to get it ! Also I wont feel so bad now when I make errors in my own presented white board calculations !
Mr. Lewin, you are a brilliant teacher. I really love your methods of teaching which make Physics extremely interesting to learn. It's a privilege for a young student like me to be watching your lectures. Thank you so much, sir, for uploading them on the web and making it accessible to all.
+Siddharth Jayshankar Thank you.
You can see a similar spectacular demo (by someone else) here th-cam.com/video/b7i2uMx7gHo/w-d-xo.html
If everyone had a teacher like you, learning would be not only easy but enjoyable :)
Thank you for all your lectures.
Thank you for your kind words.
You can see a similar spectacular demo (by someone else) here th-cam.com/video/b7i2uMx7gHo/w-d-xo.html
@@lecturesbywalterlewin.they9259 I have been watching your lectures...and You are a true GURU.
Namaste.
I found your channel by accident, and love how you teach and do your lectures. I am 60 and never went to college. I thought college was going to be like high school. If I had known there were professors like you, I would gone to college instead of going in the navy. Thank you for putting your channel up for us to watch.
Thanks for your kind words
At the shit university I attended, one of my calculus professors only showed up for half his lectures and had only a single intern in his first year of his master's attempting to teach the rest AND "correct" all our homework.
I was very blessed in that the Navy became my path to multiple degrees: Associates, Bachelors, Masters, and multiple other graduate level degrees and certificates. 10 years as an Enlisted Machinist Mate (made it to Chief before getting my commission). I retired as a Commander with a total of 38 and a half years on Active Duty. And... I am now a GS15 as the Deputy Director, Operations at Naval Supply Systems Command HQ, in Mechanicsburg, PA. My Wife and I truly love our greater Navy Family and we thank you for your service. V/r “TRACER”
All thats needed is teaching slowly and taking your time. Those teachers are the real teachers.
At 66 I have found I love your videos as a beautiful distraction from life in general. Thank you I am no longer bored.
Dear Sir, I'm a student of Engineering Physics at Politecnico di Milano. Your lectures are absolutely amazing! You have the power to make people fall in love with Physics. I wish I had you as my Physics professor.
Wow, thank you!
Our physics teacher shows us clips from your videos since demonstrations are not possible in our tiny classrooms. Needless to say, we're hooked to you
super! great teacher
You can see a similar spectacular demo (by someone else) here th-cam.com/video/b7i2uMx7gHo/w-d-xo.html
if your teacher needs to show you this video in class, you might as well stay home and teach yourself with youtube videos.
He probably just shows them the demonstrations if I had to guess, not replacing his own lectures with that of Walter Lewin's, great as they are. When you're in a tiny classroom, demonstrations are hard, so these videos are used to supplement that where demonstrations would take place. I've seen instructors do that in other classes when the room is too small, too. You have to work with what you're dealt.
Same here.
Sir walter lewin I am in class 10th from India.I was very bad in physics and didn't liked it but because of you I am addicted to physics that even I am now able to understand these topics Thank you very much.And we all students are gglad that we have the greatest teacher of all time.
Lectures with applied demos and derivations are always better than an entire lecture of numerical problems. Great lecture!
You can see a similar spectacular demo (by someone else) here th-cam.com/video/b7i2uMx7gHo/w-d-xo.html
at 71 and having Physics more than 40 years ago I am so very thankful that my instructors taught me just like Walter is doing, with "concepts" not just math! Those concepts have been able to be applied by me in the fields of electronics and electricity, carpentry, welding, even cooking food. Building houses and barns. I would say that the concepts are more important than the math, a calculator/slide rule can do math but it can't analyze a concept!
Do u know the meaning of life
@@user-dw2df4ke8x is it sarcastic?or serious?
Lectures by Walter Lewin. They will make you ♥ Physics.
th-cam.com/channels/iEHVhv0SBMpP75JbzJShqw.html
300+ videos. Many of them with high resolution. The ♥ channel has all my lectures and talks.
Yes I am Walter Lewin. I was 43 years Professor of Physics at MIT.
ok
If this really is you Walter, thank you so much for what you do.
Yes, Greg, I am the REAL Walter Lewin and I run this channel.
Thank God you are back.
This legend is growing old 😢 if he dies the world will miss a genius.
funny that some students are not satisfied with this kind of lectures... I find them inspiring and so clear! I wish I had such kind of teachers at university...
Now I think I'll be addicted to the sir's lectures, truly great and amazing to learn!!!
When you teach,I don't feel like you're teaching a subject but teaching reality and truths.
My old physics teacher was this passionate, I loved physics and because of him I do not stand confused looking at something that seems like magic, in my head I'm thinking of all the laws of thermodynamics and try to figure out where the magic comes from.
I’m a class 12 student from India, and I have all the topics covered here in my JEE syllabus. The lecture was truly very interesting and helpful. Thanks a lot sir ❤
What a fantastic teacher! His students are very lucky.
Yep
So is
Entire physics world is dependent on your lectures. In other words not only the students sitting before you are learning. Your lecture videos are seen by rest of the world
I'm an ignorant human being. This guy is the teacher that if he was at the right place and time in my life, now I was an astronaut . Well done. The world needs more teachers like you. 🙋♂️Greetings from Tuscany .
He's the real doc from Back to the Future.
You can see a similar spectacular demo (by someone else) here th-cam.com/video/b7i2uMx7gHo/w-d-xo.html
Haha! I was thinking the exact same thing but only a much calmer and low key Doc! How funny! LMFAO!
I’m in physics 2 this semester. I wish I could have such a professor! Now I have to study on my own by watching helpful videos. I never watch TV, instead I watch TH-cam a lot. This video is so fun!
Hey can you explain me what's normal physics and physics ll in college? I am in high school and have studied this already
Not all heroes wear capes. Thanks a lot!
Regards from Argentina.
You can see a similar spectacular demo (by someone else) here th-cam.com/video/b7i2uMx7gHo/w-d-xo.html
Some capes are bathrobes
Who say hero wear caps
this is the best youtube comment of all time. i love it! i will use this line too! and credit you. cheers mate!
"...Concepts is what matters ..." 3:15 that is the heart of physics ; understanding the concepts, and how they connect with each other.
Physics is very easy to understand with your lectures professor.
🤩🤩 yes
I understood almost everything you taught in this lecture as a 10th grader . Sir you are an amazing teacher. Love from India ❤️🇮🇳😃
The last 10 minutes of the video perfectly explained how great of a teacher you are,sir.
Sir I'm from India and I wanna say that by seeing ur lectures I fall in love with physics 😊😊😊
Currently, I'm preparing for the IIT-JEE Exam, in which concepts are more important.
Thank u so much professor 🙏🙏🙏🙏🙏
how did your exam go?
How was the exam?i'm actually an IIT aspirant too.
Dear sir ,your lectures plus demonstrations is too much awesome and make the student to much excited for physics .Keep it continue sir .love from INDIA
I'm more impressed and inspired by this teacher pedagogy than his demonstrations, this is the kind of teacher I want to be
Why hasn't someone given this legend the noble prize
I'm not one of those who can easily talk about phisics, but I found myself watching these lectures and I discovered an amazing world.
I love the interjections…some professors would never highlight their mistakes
It was a slip of the pen. Slips of the pen have no consequence in what follows as the slips are not in my lecture notes!
Sir I am your biggest biggest biggest fan ........... Your teaching are very great ..... although I am in 11th , but I never intend to miss your lecture.......... Meeting you is my dream 🤩🤩.....❤️❤️love you sir❤️❤️
amazing my man. I'm going to be an atmospheric scientist, I love your lectures, love how you teach, and it's very fun to learn.
:)
I'm an Eddy current and Remote Field tech and this helped me understand the theory side of my job. Thank you.
It's amazing that such high-level lectures are available for free. Thank you for posting.
The whole Incident with ElectroBOOM was so amusing. I'm happy it happened just before I watched this lecture. Understanding the confusion helped me to digest the topic better. So thank you Dr Lewin and ElectroBoom. :)
I too am watching this video right after electroboom
Walter Lewin; such a beautiful mind, great teacher, and he tells it as it is (as currently known). Love him!
Yes just like a Beautiful Mind.
im 28 years old and didnt really care about learning for most of my life, nice to have such lectures available online, thanks
Most welcome!
Actually all this stuff is experimental. Professor makes it interesting with his demonstration. God bless you sir. You are a great teacher .
Your method of teaching is very high....your lactures are so entertaining and increasing my curiosity to learn physics....thank u professor...
Studying from the best teacher in the world. What a feeling!!! 🥰🥰🥰♥️♥️
Its incredible that anyone can talk to a highly qualified person like and get a response at the comfort of their homes. Thank you
Sir, what an amazing teacher you are, i'll never forget this lecture❤
Shapes! Colors! Pretty letters!
Legit gonna die slightly less on my finals now, tysm
At MIT : WHAT!! homework too long?? Ok i cut out 2 questions u do only 7
At Schools : WHAT!! homework too long?? Ok rewrite it 2 times and from tomorrow 10 questions instead of 8 + detention+ guardian call+1 week suspension+ 10 point deducted from you final grades for complaining...
That's college vs school.
@@Speed001 that's the world vs india
@@sahilsagwekar If you don't know let me tell you There are so many countries where the school system is like this and more worst than India.
@@hardeoupadhyay3792 I agree with you . Eg.china ,south korea..
I am a sixth-year science student from Iraq and I thank you for your excellent explanation. I benefited from it ♥️
you are most welcome
I demonstrated at the end of my lecture #16 of my 8.02 E&M course at MIT that two identical voltmeters attached to the same 2 points in a circuit can show very different values. th-cam.com/users/th-cam.com/video/nGQbA2jwkWI/w-d-xo.html
This can also be demonstrated with a transformer.
th-cam.com/video/b7i2uMx7gHo/w-d-xo.html
The reason is that an induced EMF (Faraday's Law) creates a non-conservative E field. When a voltmeter reads a value V it means that the integral of E dot dL across the voltmeter is V.
In cases where Kirchhoff's loop rule (KVL) applies, 2 voltmeters attached to the same 2 points in a circuit will always show the same value. Kirchhoff's original text can be found in the following link, pages 497-514: books.google.de/books?id=Ig8t8yIz20UC. Clearly he was fully aware of the prerequisite for his "loop rule". KVL is a special case of Faraday's Law. That's why Faraday's Law is one of Maxwell's equations and KVL is not.
My demo was first suggested and published by Romer in December 1982 in the American Journal of Physics. This demo has now become a classic; it's done all over the world at many colleges and universities.
*ElectroBOOM and Dirk Van Meirvenne believe that 2 voltmeters attached to the same 2 points in a circuit must always show the same value which is not true.* They each posted a video on their channel in which they claim to have proof for their wrong ideas.
Also read Professor John Belcher's thoughts on Faraday's Law and on KVL. Professor Belcher is my former colleague at MIT. freepdfhosting.com/0813df09f5.pdf
*ElectroBOOM insulted me in his video by mentioning that the reason why my 2 voltmeters read different values was due to "bad probing". He stated that if I had done the demo correctly I would have found that both voltmeters would have read the same value. He could not have been more wrong.*
The following video may also help some of you to understand why 2 voltmeters attached to the same 2 points in a circuit can give very different readings. th-cam.com/video/T6S5VS03xZc/w-d-xo.html
I thank Mick Vall for his insightful msgs.
Hello sir 😃❤️
Love from alakh pandey sir and india 😃❤️🇮🇳
Thank you very much for the linked video, it really adds value. I guess the problem why it seems so weird is that people often forget that voltage isn't just one dimensional along the wire, but instead the potential difference of a field which is multidimensional with a direction within the space. All the typical simplifications seems to hurt a lot to understand the demonstration at the end and why it matters how the voltmeter is placed.
Yes yes, but after you reduced the homework by 25%...What happened to test scores?
Thank you for insight. Some people don't understand things and stick with orthodox belief. It is very eye opening for me
😅 I have a lab due next month by watching this video you’ve clarified a lot of things. Thank you 🤗
These videos gave me a better education and a genuine love of physics that the education system nearly beat out of me.
That's what MIT is good at!
You can see a similar spectacular demo (by someone else) here th-cam.com/video/b7i2uMx7gHo/w-d-xo.html
LOL I enjoy the electronics refresher TBH ... since 90% of electronics is Physics the rest is just Murphy's law ;) lol
indeed sir, you are among the greatest teachers of physics to ever exist. love from India🙏
Yours concept and way of teaching is so Clear and 90% Students can understand ❤️
legendary work💖
Lots of love sir from Nepal🇳🇵😊💖
0:33 "If you are very unhappy with your recitation instructor, you are complete IDIOTS, if you stay in that recitation!"
I truly love this!
"Some are better than others... that's the way it goes in life" 0:55
My respect to you, Sir. Knowledge is always heavenly!
dear prof. Walter LEwin sir, its very true indeed that we are being taught these things in class 11 and 12
these concepts are never explained correctly and we r told to mug them up without demonstration or anything
u r a life saver
i owe u one :)
thanks a lot
36:02 ......made me remember that anythings possible! I absolutely love all of Walters lectures!
The best lectures on physics I've ever seen. (I studied physics in Germany and I am a retired teacher now.)
Professor you never fail to amaze me.... Lots of love for saving my exams
I'm nearly 50 only got the bug of physics don't understand the maths but. I understand the concepts from the cmb to the quarks down from atoms ..just wish I'd have known this when I was young but my high school teachers never inspired me ,your amazing Mr Lewin thanks
Awesome! It takes an extraordinary professor to make this material fun and interesting. Good job.
I always find myself in these videos, very good job. Thanks to you, we understand and love physics too
The oscilloscopes form a second conductive loop around the energizing coil. Although an oscilloscope is concidered to be a voltage measuring device, in this case they are measuring the current that flows in a clockwise direction around the loop that they form. The righthand oscilloscope see's current flowing into its positive terminal, the leftthand oscilloscope see's current flowing into its negitive terminal and so shows a mirror image. The different amplitude of the two displayed waveforms is caused by the different values of the resistors in parallel with the one megohm resistance of each oscilloscope.
If you simply move one oscilloscope to the other side of the coil without changing the connection points of that oscilloscope, both oscilloscopes will now display the same waveform.
what you wrote is correct. The fact remains that 2 identical voltmeters attached the the SAME 2 points in a circuit can read VERY different values and that's because of Faraday's Law. This shows that Kirchhoff's loop rule cannot be applied here.
You can see a similar spectacular demo (by someone else) here th-cam.com/video/b7i2uMx7gHo/w-d-xo.html
@@lecturesbywalterlewin.they9259 But the two voltmeters are *NOT* attached to the same 2 points in the circuit if one meter is connected correctly and the other is connected incorrectly. The ends of the wires leading up to the meter are not necessarily at the same potential as the terminals of the measurement device inside the meter!
@@RWoody1995 you are mistaken. the wires have zero resistance.
In the case of an induced emf the potentials in a circuit are no longer determined, they depend on the path and thus *Kirchhoff's Loop Rule is not valid.* Kirchhoff's Loop Rule is a special case of Faraday's Law (namely when phi/dt=0). Thus *Faraday's Law is always valid.* The following videos may help you to understand this. This is very basic Physics I will therefore not argue with anyone about this.
th-cam.com/video/f3-SfzepuPs/w-d-xo.html*LOcvkaSY-IZqheFYM5
th-cam.com/video/5be3zpj_eCY/w-d-xo.html
th-cam.com/video/wz_GqO-Urk4/w-d-xo.html
th-cam.com/video/b7i2uMx7gHo/w-d-xo.html
@@lecturesbywalterlewin.they9259
Well, those voltmeters, though connected to the same points, HAVE to stay on opposing sides of the solenoid. Thus, voltmeter on the right forms closed loop with the resistor on the left, with solenoid inside this loop, whereas voltmeter on the left forms a loop with the resistor on the right, again with solenoid INSIDE this loop.
Thus, strictly speaking, those are NOT identical voltmeters, what each of them shows depends on where exactly around the solenoid it is placed and how the wires are laid down, not just where they are connected. If you place both of them, let say, on top of the assembly right on the solenoid axis and far away, put all wires bundled, well, then they will show the same values.
I can assure you that if I would be going to college. The professor who I would take is Mr. Walter Lewin. YOU ARE THE MAN FOR SURE. Keep up the great work.
In the case of induced EMF potential differences depend on the path - that's one of the concequences of Faraday's Law.
@@lecturesbywalterlewin.they9259 I can tell you that I love physics
Sir im watching your lectures during this pandemic and enjoying physics demonstration. I'm in 10th standard but I love ur videos and practicals. I pray to god that one day I'll meet you and we both do experiments by applying physics rules😂.I believe u as my friend rather than a physics teacher 😇#LOVEFROMINDIA
Keep it up
@@lecturesbywalterlewin.they9259 Sir do you have lectures clearing the difference between potential difference and EMF ? I am confused
@@jayeshmhaske8839 all cows are animals but all animals are not cows. All EMFs are potential differences but not all potential differences are EMFs - use google
I wish I could take his courses. I'd love it!
I think we should replace all schools and shitty teachers with youtube videos on topics. The good teachers will make there money from TH-cam views, the shitty teachers will disappear and we won't waste our money with a shit education. This was a great lecture! Thank you so much!
just remember that kids need empathy and companion, and not only super awesome teachers ,
I can't ask youtube questions unfortunately.
But you can learn to search Google and response by yourself any question.
:)
Feruhlphox I could see a good place for such an idea. Schools could post all of their classroom sessions and the schools received the proceeds.
The benefits: the schools would have more money to pay their teachers, as well as buying content and supplies.
The schools would have a higher incentive to seek out and promote higher quality instructors.
Schools would be better able to monitor their instructor's performance.
Teachers would have more incentive to be better.
Students would have access to lectures when their out (sickness, etc).
Students would also need to behave (or the world would see them act a fool).
Sir, you are an excellent teacher and educating thousands of people everyday. I pray to God that I'll meet you in future. Thank You so much sir 👍
Dr. Emmett Brown, could you PLEASE take me back to the future so that I can come to your classes in real life...
sir your teaching is the best teaching in the world
Great lecture!I love your demo at the end of this lecture!
I have taken 18.02 before 8.02,I think it was a right choice.Because I have fully understood the word potential,non-/conservative field.
I learned a lot from this lecture.Thank you prof.Lewin.😁
Greatest thing i found here is..to watch this lecture being a agriculture student...who dont have any connection with physics😎
Love to watch your lectures sir🙋🏻♂️
So nice of you
Here in India , we studied it in our NCERT class 12 chapter ( EMI ) on this whole topic.....
And i have an exam tomorrow of this😅
Same here in sri lanka class 12 lmao 😂😅
No offense dude
You need to study all of this again
When you are in Bsc
Believe me you got 2 semester of electrodynamics
By Griffith
Students today in India doesn't want to enjoy Physics, they just memorize formulas to quickly solve MCQs to go into IIT, I pity them
@@edunitianmanab2836 It's not their fault, it's because of the system. No one cares how much a student knows.
It is the basic you are studying,it will be needed if you take physics or engineering in the future,there you will study the practical aspects of it.
Go to 5:00 for actual lecture.
thanks
thanks yo
You can see a similar spectacular demo (by someone else) here th-cam.com/video/b7i2uMx7gHo/w-d-xo.html
Thank bro for Saving our time
Thanks !!
"Concepts is what matters." (3:16)
You can see a similar spectacular demo (by someone else) here th-cam.com/video/b7i2uMx7gHo/w-d-xo.html
THIS is how you teach a class. Give real world examples beside your theory.
Idk why but the way he draws and write on the board is so fkin beautiful for some reasons..
I love your way of teaching sir, thank you for sharing your knowledge
You’re very good in explaining all these simple physics, and with your heart, you may find a way to explain what it should be in zero point energy field accessing anti-gravity technology that still hidden to you.
Whyyyy!? theoretical physics always sacrificed for technology!?
Thank you for leaving in the portion about student complaints. As a teacher, it's helpful to remember that even the best of us can't be perfect for everybody. You are an amazing teacher and you inspire many people.
it is shocking that countless people have misconceptions about Faraday's Law. Even more shocking that the authors of most college books also have no clue (including Giancoli the book I used for 8.02).
I always saw people say "I wish he was my teachers" when I watched this in high school. Now that I am studying at university I can understand the feeling. This is brilliant, especially during the current shitshow. Our pre-recorded lectures in electromagnetism are like a teenagers physics presentation compared to this, with worse audio and demonstrations than this way older video
No words for your hardwork....
Great work👌👌👌
I wish I had a teacher like you in high school.
Thank you Walter
Another outstanding lecture. As an electrical engineer who has worked with transformers, this lecture has helped me to answer one question that was not clearly answered, where is the transformed voltage? It is electromagnetics explained in a concise, simple but powerful way. God bless you Professor !
He's the man. I mean really he explains one of the most complex topics like a piece of cake.
Is this is complex topic then Britishers is very duffers
This lecture helped me to clear my concept about EMI and I was able to solve 4 Questions about EMI in advance"jee" paper ..thank you sir.. you are definitely a legend .
Btw I am getting 231 in advance jee and I will ( hopefully) get in IIT's , thank you sir 😊
Wow so how's life now?
The best lectures to understand the concepts of physics can be found at "Lectures by Walter Lewin".......who makes all the topics so clear, interesting and of course enjoyable.....Thank you sir😊 for all the amazing lectures
I have been watching these lectures to prepare myself for my Electromagnetics Waves and Applications class here at MIT. Your lectures are truly phenomenal and inspiring sir!