What is an Electromagnetic Wave?
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- Опубліковано 2 чер 2024
- You might know that light can be described as a flow of particles called photons or/and as a wave depending on how you observe it. The wavelike description of light is that light is an electromagnetic wave.
But what is an electromagnetic wave?
When you dive into this question, the answer is actually quite fascinating, even if we remain within the realm of 19nth century classical physics.
In just 3 minutes of physics video, you will learn
_ What an electro-magnetic wave is (or electromagnetic radiation).
_ What is magnetic and electric about light.
_ How radio works. Yes, a radio-wave is also an electromagnetic radiation.
_ How to make a piece of metal glow light!
This video involves notions related to electric fields. For a quick refresher on electric fields, check this you-tube video:
• What is an Electric Fi...
For a deeper dive, here’s a fantastic course on the subject:
www.physics-made-easy.com/ele...
- - - - - - - - -
This video is produced and presented by Edouard Reny, Ph.D. in solid state chemistry and private tutor in Physics.
For access to great resources that will help you with your studies of high school Physics, visit and subscribe to the "Physics Made Easy" website:
www.physics-made-easy.com/
Edouard provides one-on-one private tuition in Physics (face to face or by Skype). If you wish to contact him, visit his website:
www.physics-tutor.nl/
That was well explained. But in this example we had this charged particle which was oscillating and thus generated the oscillating E field we can call EM wave. But we get EM wave when ever charged particle is in acceleration don't we? So that it doesn't need to osculate? Is there a way to explain the emission of em wave in that case? Also a student of mine asked about the phase shift of 180 degrees that occurs in the Electric Field of a EM wave, when reflected from an optically denser medium. Is there an intuitive way to explain that or is it just pure math? Thanks in advance!
Hello Visa,
Question1 (acceleration of charged particle): Yes, we do, because accelerating the charge, will create a perpendicular disturbance in the field lines (thus a variation in the direction of the E Field). A variation of the electric field is radiation. A good visualisation is provided by this video: ua-cam.com/video/uVB3G_Edim4/v-deo.html. And you can explore more with this inspiring simulation: ua-cam.com/video/oH7WRKglKNk/v-deo.html
The second question was trickier (why phase change of pi). It is hard to avoid the post high school math here… and it is true that most lecturers explain that it occurs and when, but not why…
You can roughly see it that way, by referring to the amplitude reflection coefficient Erefl/Eincident = r = (n1-n2)/(n1+n2). When n2>n1 the ratio of amplitudes is negative, implying a phase flip. More info here: www.usna.edu/Users/physics/mungan/_files/documents/Scholarship/PhaseChange.pdf
Good questions!
I hope my answers help you.
@@PhysicsMadeEasy thank you! This was exactly what I was looking for!
@@PhysicsMadeEasy When an electric wave oscillates is there a delay for when the magnetic field oscillates?
@@JL-fh4qw Hi J.L., in vacuum , no there is not: the oscillation and of the E field and that of the M field are in phase.
@@PhysicsMadeEasy please, can you provide a suggestion for a somewhat in-depth but still intuitive source on fields (classical versus quantum)? Preferably in the form of YT videos. Thanks a lot. (I've tried Sean Caroll's Biggest ideas of the universe, but cannot put those pieces together in a more or less coherent whole).
I have to say this is the first time I am starting to understand what eletromagnetic wave is. Thank you.
Omg same!
You probably never saw eugene khutoryansky
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This little video captured what miles of blackboard, chalk and textbooks couldn't. Thanks
Hi SuperGirl, I am glad you enjoyed this video. Thank you for letting me know :-)
Omg finally I found a professor I like
Good
How i wish i had a teacher like you in my life SIR.I love physics but graduated with a third class degree and still doing in teaching it in my locality nigeria. Thanks for the video my mentor.
Hi Muhdi, thank you so much for these very kind words. All my wishes for a good continuation of your studies of physics, and also my best wishes of success in inspiring young students when teaching it! :-)
This is one of the most powerful explanations I have ever seen. Please make more videos.
I sure will, thank you Bharath! There are many more on the channel. Feel free to explore!
@@PhysicsMadeEasy , thank you !
Very humble, respectful and knowledgeable person. Thank you.
This 3 minute video was enough for me to subscribe to your channel. Great stuff!
Indeed really well explained. I have seen a few videos on this topic, but you explained it the best! Well done.
Awesome explanation Sir, Hats off 🙏🏻😇 You did the explanation and theory in a calm manner , like not too speed not too slow....
Its quite fascinating...
This is the 1st video where I actually understoood EM wave and how radio works, thanks!
i haven't imagined that i could be able to understand the electromagnetic waves but after watching this i feel its amazing
It is, amazing isn't it!
And often easier to understand than many textbooks would make you think...
I lie in the title of my channel: Physics does not need to be made easy. It is already :-)
Your explanation of the topic was so clear, I never thought I could understand it so easily! Thank you 😊
Merci Celine :-)
Thanks a lot I never imagined it that way. You definitely made me understand this topic better. The relation between electron/change movement and light was just mind blowing!
it is, isn't it? That's why I like physics! :-)
Informative video
You knew exaclty what to explain how to explian, most videos skip the basic parts and go straight into concepts living us in the woods without much explianing, but you sir knew exaclty what our issues where with this topic and you explianed it to us not as if we were fellow prefesors but as if we were what we are
and that being students. THANK U KEEP IT :)
Hello Helias, thank you for your kind words...
You summed up why this channel exists: when I teach my real life students, I always make sure that the basic concepts I need to use are clear for them, otherwise, it can create or even crystallize confusion in their minds... I made this channel , focused on the basics, so that students can fly with their own wings...
Hands down the best explanation! Thanks...
That is the best explanation I have ever come across , any electrical tutor / electrician / teacher I have asked to explain this has been stumped . Thanks very much !!
Hello Jonathan, I appreciate very much you letting me know. It gives me a boost of energy and encouragement when I read that I reach my goal like this :-)
Amazing video! Thanks for your work!
For those wondering why the magnitude of E is changing:
“Alternating current (AC) is an electric current which periodically reverses direction and changes its magnitude continuously with time”
Thank you so much ❤
Question. How can it reverse directions?
@@phoumint EINSTEIN IS UNCOVERED BY DIMEGLIO:
WHAT IS E=MC2 is dimensionally consistent, AS TIME is NECESSARILY possible/potential AND actual ON/IN BALANCE; AS ELECTROMAGNETISM/energy is CLEARLY AND NECESSARILY proven to be gravity (ON/IN BALANCE); AS the rotation of WHAT IS THE MOON matches the revolution. Indeed, consider what is the man (AND THE EYE ON BALANCE) who IS standing on what is THE EARTH/ground; AS touch AND feeling BLEND; AS ELECTROMAGNETISM/energy is CLEARLY AND NECESSARILY proven to be gravity (ON/IN BALANCE). Indeed, WHAT IS GRAVITY is, ON BALANCE, an INTERACTION that cannot be shielded or blocked. GREAT. BALANCE AND completeness go hand in hand, AS it all CLEARLY makes perfect sense ON BALANCE. Magnificent.
By Frank Martin DiMeglio
The sun's tide-generating force is about half that of the moon. One half times one third is one sixth. Consider what is water. The density of what is the Sun is believed to be about one quarter of that of what is THE EARTH. The diameter of WHAT IS THE MOON is about one quarter of that of what is THE EARTH. The density of the human body is about the same as water. Lava is about three times as dense as water. Pure water is about half as dense as packed sand/wet packed sand. We can multiply one fourth times two thirds in order to ALSO get the surface gravity on the Moon in comparison with what is THE EARTH/ground. The gravity of the Sun upon the Moon is about TWICE that of what is THE EARTH. The lunar crust is about TWICE as thick on the far side of what is the Moon. Notice what is the TRANSLUCENT AND BLUE sky ON BALANCE. The maria (lunar “seas”) do occupy ONE THIRD of the visible near side of what is the Moon. One half times one third is one sixth. What is E=MC2 is taken directly from F=ma, AS TIME is NECESSARILY possible/potential AND actual ON/IN BALANCE; AS ELECTROMAGNETISM/energy is CLEARLY AND NECESSARILY proven to be gravity (ON/IN BALANCE); AS the rotation of WHAT IS THE MOON matches the revolution. Consider what is the orange AND setting Sun ON BALANCE. Consider what is THE EYE ON BALANCE. Consider what is the fully illuminated AND setting/WHITE MOON ON BALANCE !!! What is E=MC2 is dimensionally consistent. The land surface area of what is THE EARTH is 29 percent. This is EXACTLY between (ON BALANCE) what is one third AND what is one fourth. The maria occupy one sixth of what is the Moon. The BULK DENSITY of what is the Moon is comparable to that of (volcanic) basaltic lavas on what is THE EARTH/ground. Consider what are the tides. ONE HALF times one third is one sixth. ONE QUARTER times two thirds is one sixth. What is gravity is, ON BALANCE, an INTERACTION that cannot be shielded or blocked. CLEAR water comes from what is THE EYE (ON BALANCE). ON BALANCE, what is THE EARTH is ALSO BLUE !!! GREAT. BALANCE AND completeness go hand in hand. What is LAVA IS ORANGE, AND it is even blood red. Awesome. Yellow is the hottest color of lava. Blue is the hottest flame color. Note: Consider what is the blue flame. The lunar surface is chiefly composed of pumice.
By Frank Martin DiMeglio
In understanding SPACE, what is gravity, TIME, AND time dilation (ON BALANCE), it is important is it to understand what is a BALANCED displacement of what is SPACE. ELECTROMAGNETISM/energy is gravity ON/IN BALANCE.
Consider what is E=MC2. TIME is NECESSARILY possible/potential AND actual ON/IN BALANCE. Consider TIME AND time dilation ON BALANCE. (c squared CLEARLY represents a dimension of SPACE ON BALANCE.) Indeed, the stars are POINTS in the night sky ON BALANCE. The rotation of WHAT IS THE MOON matches the revolution. Consider what is THE EYE, AND notice what is the TRANSLUCENT AND BLUE sky ON BALANCE. NOW, consider what is the BALANCED MIDDLE DISTANCE in/of SPACE. CLEARLY, BALANCED inertia/INERTIAL RESISTANCE is fundamental (ON BALANCE). “Mass"/ENERGY IS GRAVITY. ON BALANCE, consider what is the orange (AND setting) Sun. “Mass"/ENERGY involves BALANCED inertia/INERTIAL RESISTANCE consistent WITH/as what is BALANCED electromagnetic/gravitational force/ENERGY, AS ELECTROMAGNETISM/energy is CLEARLY AND NECESSARILY proven to be gravity (ON/IN BALANCE); AS gravity/acceleration involves BALANCED inertia/INERTIAL RESISTANCE (ON BALANCE) consistent WITH E=MC2, F=ma, TIME, AND time dilation ON BALANCE. This CLEARLY AND NECESSARILY represents, DESCRIBES, AND INVOLVES what is possible/potential AND actual ON/IN BALANCE, AS ELECTROMAGNETISM/energy is CLEARLY (AND NECESSARILY) proven to be gravity (ON/IN BALANCE). Notice what is the fully illuminated (AND setting/WHITE) MOON ON BALANCE. Great. TIME is NECESSARILY possible/potential AND actual ON/IN BALANCE. Indeed, inertia/INERTIAL RESISTANCE is proportional to (or BALANCED with/AS) GRAVITATIONAL force/ENERGY; AS ELECTROMAGNETISM/energy is CLEARLY AND NECESSARILY proven to be gravity (ON/IN BALANCE). This CLEARLY explains what is E=MC2 AND F=ma ON BALANCE, AS TIME is NECESSARILY possible/potential AND actual ON/IN BALANCE !! (Consider TIME AND time dilation ON BALANCE.) Great. Indeed, consider WHAT IS THE EARTH/ground ON BALANCE. I have mathematically proven why the rotation of WHAT IS THE MOON matches the revolution, AS ELECTROMAGNETISM/energy is CLEARLY (AND NECESSARILY) proven to be gravity (ON/IN BALANCE). Consider TIME AND time dilation ON BALANCE, AS the stars AND PLANETS are POINTS in the night sky ON BALANCE; AS c squared CLEARLY represents a dimension of SPACE ON BALANCE. (Consider what is THE EYE ON BALANCE.) I have mathematically proven what is the fourth dimension, AS ELECTROMAGNETISM/energy is CLEARLY AND NECESSARILY proven to be gravity (ON/IN BALANCE) !!! I have explained why what are OBJECTS may fall at the SAME RATE.
By Frank Martin DiMeglio
@@Lorenzo-zg3ct You have to reverse voltage, assuming you have battery then change + with - and vice versa :) If you do it more more frequently then you have AC current :D
Beautifully explained.
I love your work! thank you for making Physics not just easy but cool!
Thank you for rescuing me out of all the confusion on em waves. Your 3 minute presentation is worth the research of a lifetime.
🙏🙏🙏🙏
Thank you so much Imallright. Some people spend a lifetime of research looking for complex things, which is good and useful for society. Surprisingly, it needs also a lot of time and teaching experience to present basic concepts in a pedagogical way while remaining rigorous... (I wished I had me when I was a student lol!)
So far d most comprehensive explanation of electromagnetic waves available on Internet .....!!!! Thank you 🙏
You are welcome. I am glad that this video brings a little clarity to so many!
What a masterpiece of explanation. It's amazing how with a combination of videos we can understand great things.
Hello Byynx, thank so much for your kind words. I am so glad that my work enlightens people on the wonders of our universe! Comments like yours make me feel like achieving my goals 😊
🎉❤😢
Complicated concepts made easy! Great job!
Very simple short and concise
Awesome video as always!
Excellent explanation! Thanks
Excellent explanation, thank you
Great video sir 👏👏
Excellent explanation. Thank you.
Extremely underrated 😭
Thank You for this easy to understand explanation..
thank you for this amazing video explanation sir !!⚡💡
Very well explained... Thank you
Thanks, great explanation
This art in explaining physics thankyou😊
That was spectacular!
So short, crisp and to the point. Thanks teacher
You are welcome... That's what I try to do: Make physics easy. Thank you for your kind feedback :-)
Brilliant sir. Thank you.
Thank you for this information.
Great explanation
I love the way he says cosine 1:10
Wow. Thank you so much. I self-taught AP physics 1 and 2, and got 4 on both the exams, but I was struggling to grasp this concept for so long. You made it so easy to understand this. I wish I found you 2 years ago.
a 4 in AP Physics while self taught. Well done! Thank you so much for the kind words!
Thank you so much for the encouragement. Please keep up with your good work. That help students like me a lot.
NICELY DONE 😊😊😊❤❤❤❤ I AM HAPPY FOR YOU 👍🏿👍🏿👍🏿🙏🏿🙏🏿🙏🏿✌🏿✌🏿✌🏿👊🏿👊🏿👊🏿
Amazing explanation!
THANK YOU SO MUCH I HAVE BEEN HAVING A HARD UNDERSTANDING THIS AND YOU CLEARED IT UP THANK YOU!!!!🙏🙏
Keep going fav physics teacherrr❤
You made it so easy to understand
Loved it. Clearly explained in such a short span!
Hi Vanshita, thank you for letting me know you enjoyed the video :-)
This is excellent, thank you.
This was great. I love a short, precise explanation!
Hi Dan, I am glad you liked it. Thx for the feedback :-)
I failed A- Level Physics in 1972. I found the level of abstraction was very demanding. 'Using Newton's equations of motion, explain how a horse can pull a cart along a horizonatl track'. I felt there was 'Something Deply Hidden'. Give me one of Sean Carroll's multiverse wave functions any day....
June 1972! I was just one year old then, so obviously I do not know how the A-Level exams were at the time.
But today, this type of question still exists. It's a bit of a late advice, haha, but what I usually say to my students taking A-Level Physics is to work on many past papers in order to understand the A-Level exam philosophy and its pattens. Yes even if you have a good abstract understanding, it may not be the one they want to see (i.e. no specific 'marking' keywords in your explanation), and you could end up with a fail. There is a way to answer these questions and get full mark, and this is attainable by 'learning the exam'.
Thanks for the reference to Sean Carroll's. I didn't know about him so checked him out, looks super interesting. Is he a modern Everett? I am ordering a book to check it out thank to your comment!
Thanks sir making physics easy ❤️
I just stumbled onto this video and i hope you never stop creating more videos
Thank you Mubin for your kind words. It's true I haven't posted a video for a while: so much on my plate right now! But making new videos is the plan, so expect a burst of new fun physics videos when the time comes!
Well explained! Thank you
You are welcome Spammer :-)
Wwow.. really physics made easy.. thank you very much sir..
Great 👍
This was cool af. Thanks for posting!
Wish we had these excellent, graphic learning-assist videos when I was doing electrical engineering at 'Varsity in the early 1970s
Thank you Max for your comment, especially that I do the graphics myself (just using Powerpoint :-) ).
Oh, and I agree. Sometimes I think that if I had access UA-cam material when I was a student (late 80s, early 90s), my life as a student would have been much less painful, and I probably would have won a bunch of Nobel prizes since haha!
Yet, the grass appears always greener elsewhere: I still wonder why the average level of young people in maths and sciences has been falling these last few decades (according to many statistics).
It's quite counterintuitive...
Very easy to follow but very informative.
Thank you sir short and sweet
Great example and explanation. Great work, thank you.
You are welcome, I am glad it helped!
REALLY LIKED THIS EPIC EXPLAINATION SIR.
LOVE FROM INDIA❤️
Great video
Well explained
Thank you for this sir.
Well explained.
Lots of love 😍😍😍
Finally I understand the what is electromagnetic wave actually. Thank you Professor, May Allah Subhanahuwataala bless u.
Thank you Muhammad for your kind wish. I am glad my video helped you.
@@PhysicsMadeEasy thanks for sharing your simple information 🙏👍
Very nice!!!
awesome! 😊
sir I can't thank you in words . ❤️❤️ I don't know why all teachers are not like you . my teacher explained me and whole UA-cam explained me but I was not getting feel of this topic . I was able to solve em wave numericals but wasn't understanding what's happening in real . but now my all concepts are crystal clear.
again thank you so much 🙏🏻🙏🏻🙏🏻💖. I have subscribed your channel and pray for millions of subscriber on you channel . ❤️🙏🏻🙏🏻🙏🏻
Thank Sunny, I am super happy that this video helped you so much! Please keep praying for that milliion subs... It's quite a long way haha. It would make me euphoric though to know my work helped so many people !
Very nicely explained. Thank you.
You are warmly welcome
The explanation was superb! I learned a lot in a span of almost 4minutes than our 1hr class discussion. Thumbs-up! 👍👌
I’m teaching this stuff and taking a lot of notes. Lol.
@@jacobchristner7129 Well you might as well start teaching the right stuff: No more magnetic fields, only electric charge.
@@jacobchristner7129 If you are teaching this stuff then answer me: what causes the speed of light?
Very informative.
Bestest video ever made on this topic.
Thanku so much sir!💜
Thank you very much for your comment Aditi. I am glad you enjoyed the video :-).
Awesome explanation.👌
Thank you 🙏
I am glad you enjoyed it Paruthi, Thank you for your kind words
Just discovered your channel. Very enjoyable viewing. Love your style of presentation. New sub.
Hello Rich. I am glad you enjoyed your visit to my channel. Thank you for you kind and encouraging words. You are welcome to visit again anytime :-)!
Nicely explained. My Physics teacher never said about this.
Merci beaucoup pour cette vidéo !
Thank you sir.
Outstanding Video!
Thank you Samiul
Best explanation
amazing 🤯 thank you
Loving this
This was by far the easiest explanation that I have encountered.
I am glad you enjoyed my approach. Thanks for letting me know :-)
What an amazing video! Thanks!
Hello Juno, I am glad you enjoyed it. Thank you for your encouragement!
You are a magnificent maestro!
Thank you for the explanation, sir. Definitely sharing this video and channel with my friend.
Hi Moe, I am glad you enjoyed it and that it was useful to you!
That was just awesome.
An informative video
Thank you so much. What a nice presentation of electromagnetic wave.
You are welcome, and I am glad you liked it.
Amazinggg!!
What a video sir. Fantastic.
Thank you Rajesh!
I must say this vdo is quite short and at the same time informative too along with an intuitive understanding 👍
Thank you Samishka :-)
You are an amazing explainer.Keep doing such work that can help us.Thanks a lot for making.
Hello Nazmul, thank you for your kind words. They encourage me!
And u encourage me to learn more.
Thank you for the video. Subscribed.🌱
Welcome to Physics Made Easy Berni. Feel free to explore!
Thank you for this!
You are very much welcome :-)
I'm brazilian, finally i can understand it, this is, learn how eletromagnetic waves are origninated. Thanks!!!
Hi Tomas, then it means my video has reached it's goal. Thank for the feedback, it's motivating!
This was definitely amazing! I was looking for an explanation how electromagnetic waves work or travel, and this was the video that finally made me understand the whole concept. But here are some questions, the oscillating electrons create the oscillating electric field which results in EM waves, so does this wave go on forever? Does it not get weakened as it travels? If so, then does light get weaker too as it travels (Which I think yes)? And is that the same reason we see faded light when it comes from a distance?
And how was the very first light created without an oscillating charge?
Thanks a lot! Your videos are great, keep it up~
Hello Sakib,
- The oscillating electrons create the oscillating electric field which results in EM waves, so does this wave go on forever? -
If there is no other electric field to disturb it on the way, yes it will.
- Does it not get weakened as it travels? - In a purely static space empty of gravitational mass, no, it will not lose energy and go on forever.
- If so, then does light get weaker too as it travels (Which I think yes)? -
Light is the sum of rays. Each ray is an electromagnetic wave. A light source (or antenna) emits in all directions. Draw a point on a piece of paper (the source of light). Draw twelve lines going away of that point (in different directions). What you perceive as the intensity of light, is the concentration of these lines. You see they are more concentrated close to the source than when they are away… That is what you perceive as the weakening of light. But each line stays a line of the same thickness, each ray conserves its energy…
- And how was the very first light created without an oscillating charge? -
You mean at the beginning of the Universe? Charges were there before light (electric charge is a conserved property).
@@PhysicsMadeEasy Thanks a lot! This explains my question~