What is Light? Maxwell and the Electromagnetic Spectrum
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- Опубликовано: 22 июл 2024
- Up until a couple centuries ago, we had no idea what light is. It seems like magic, no? But there is no magic in this world, really. Just stuff we don't understand. So let's understand light a little better right now, through James Clerk Maxwell and the electromagnetic spectrum.
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“Light travels faster than sound. This is why some people appear bright until you hear them speak.”
No, it such mere deceptions can't be measured by naked eyes.
XD
Oh my God🤣🤣
Wise words.
Except there is a lot more going on that we can't see than people realise. I don't need to hear someone speak to know if they are ' enlightened ' or not ;)
I lowkey was waiting for him to say, OK, let me shed some light on this subject
Science Revolution what the fuuuuuu
@Science Revolution Dude thats an amazing explanation thank you
wasted opportunity xD
@Science Revolution we call this "dumb assery"
I’ll never know what science revolution said. My life will never be complete
explained in 4 mins what my lecturer failed to explain in 40 mins
Omg I came here for my psycholinguistics homework two videos ago and I just can't stop watching you! I loved so much the review at the end. What a great teacher! This BA Mexican student is sooo happy!
Reality is so weird.
I have no words for the way u are presenting the topic for us. Pls keep making such videos with animations and images. Also try to make some videos related to the IIT-JEE prep, I would love it.
I’m very disappointed, there was so much room for a light 💡 dad joke somewhere in there haha.
Awesome vid again, Thanks Prof Dave! Science is addictive, or my ocd has nothing else to focus. Either way I’m enjoying learning, bit by bit.
They way it’s all sectioned out makes your page extremely easy to reference.
Explain it to me like I’m 4yrs old and we are all good. Love it haha 😂
Hi, I’m very confused. Why some say “light particle doesn’t has neutral charge”, when is supposed to be the same exact thing. If I compare transmittion of electric waves over copper vs light over (well, inside) optic fiber, I can catch that maybe because of wavelenght another conductor is needed. But there are other reactions that are different, looks like light can’t give you a shock, but electricity certainly can. Thnx in advance!
question why isn't the b field a cos wave . Because if we see the slope of E field at points near the origin we have dE/dt maximum and Maxwell equation describes when change of electric flux is maximum magnetic field induced is maximum. I cannot find this answer if u have time plZ solve this querry.
I find your videos really good to watch
Does the full range of the EMS measure from a Planck frequency on the low end (zero?) to an upper Planck length frequency on the gamma end? I can not find an answer to this anywhere!
1:11
*I am confused that why people represent the wave like the above one instead of the below one which is real ?*
u have ur own aesthetic of a science teacher thats actually cool
plz tell whether the wavelength are separated or in a line like first blue then......
Does EM waves present everywhere as full range with all types of waves? If an object absorb some visible light what does it mean? Does it mean that visible spectrum only incident the object and some Wavelengths are absorbed and some reflected?Or EM wave with full range hit that object first , and object absorbs only visible light ?
What is Light? Baby don't hurt me, don't hurt me, no more.
Please provide me the link of how electromagnetic feild is produced
Good stuff man. I love the quick mask cutouts!
If different wavelengths means different colours, than why colour do not change with refraction where the wavelengths change and become shorter? Thanks in advance
All my life I've only ever been on the Autism Spectrum, so this is a very helpful video, thanks
Best explanation 👍
Do we know absolutely that there is no more to the spectrum, or have we just not discovered any new way to record what may be beyond? Stupid question. I know but how can we test it or find a way to test it? Good use of Horus BTW.
Very informative vids. Keep it up buddy lol👍🏾
Way to go Dave! Started watching your videos even when not studying! And damn you hit me with a quiz at the end (really good idea actually!). Will support you $ when out of grad school (lol)! Can't wait for next one!
future money is almost as good as now money! and leisure watching is good too :)
If light is a electromagnet wave then can we produce current if we keep a Cooper coil under the sunlights ?
Thank you sir this helped a lot.
Can you explain how the wave nature of light causes refraction of light?
Do a playlist on Inorganic chemistry
THANKS! this was to the point and very comprehendable.
one doubt though, why is is that electromagnetic radiations are not deflected by electrical and magetic feilds ?
This is so good ! Light or electric magnetic wave is a wave of oscillating electric and magnetic fields perpendicular to each other and the dire tion of their propogation... Wow that animation was awesome 💯 explained everything
(I) Electromagnetic waves
(ii) Electric field & Magnetic fields
(iii)3*10^8 m/s
If the frequency is 1x10^11hertz then it belongs to infrated right?
That was the best intro ever
Yaa😆😆
That's an introductory intro.
Hi
This is exactly what i was looking for
Very nice video, helped a lot
Not gonna lie when my teacher for general science all I could think of was how much Dave looks like *jEsUs*
Not at all
At least I do not think so
Y’all Jesus was black or at least I think so. The bible didn’t mention his color
Are all wavelengths in the electromagnetic spectrum polarizable as with visible light? Thx
Yes, we can find polarized EM radiation of all kinds, either manmade or natural. Since EM waves are transverse, all of them have a polarization. And a group of them could either have an organized polarization, or a mass assortment of polarization that we'd call unpolarized.
Some examples:
UV is naturally polarized as it fills our blue sky background.
AM radio is linearly polarized vertically by the working principles of the antenna orientation, while FM radio is intentionally polarized with a circular polarization to improve reception on any receiver's antenna orientation.
I’m not sure if my comment is still here but what’s your take on the deconstructive interference at a photo detector that makes it look like there is no energy at that spot in time but the next plank length forward or back the two photons would have been observed 🧐 dark matter and energy?
Hi Dave Hydrogen gas bombardment in a Car piston is light and heat also air pressure. The lobestone turn it to electrical magnetic field the steel in the piston connect to lobestone shell turn it to electrical field Dave question can CarS not crash to each other if each Car are magnetic field.
I like the question part in the ending
Thanks Professor Dave!
Love these videos. Thank you
Good Explanation
What if matter is just more of the electromagnetic spectrum but after protons have gained more mass by attracting an electron but still part of that spectrum?
I wish professor Dave would cite his sources in his youtube vids :,( i always use his vids to write essays for my science classes
i usually just work directly out of a textbook! and i find them all the be rather similar
Professor Dave Explains omg he replied 🤩 lol ok so I’ll cite any textbook I use. your vids are just so I can understand what’s being said in the textbook. Got it. Thank you!!!
And so, wavelength determines color while amplitude determines chroma? Extreme Amplitude is bounded between black and white, All color to no color? Or is it, max visible amplitude results in highest color intensity and the energy level either goes to white light ( high energy) or no light ( low energy).
Sir can you make a video on
Emission adsorption spectra
i cover that a bit in the bohr model, i talk about it a bit in the astronomy series with the spectral classification of stars
I remember watching this forever ago for gen chem and now I'm taking ochem 2 I need to review it so I can figure out spectroscopy
Hi Dave. I love your videos...very informative. Question - I read that a photon has no mass. Does that pertain only to a 'resting' photon, and they gain mass only when moving (which they essentially always do or we wouldn't see anything)? If a photon has no mass, and gravity affects objects with mass, how does a black hole attract photons so strongly they can't escape? wouldn't they be unaffected if they are massless? It may be a stupid q, but I'm no physicist so figured you might could help me out with this one...thanks!
Always massless, so with black holes it's about the warping of spacetime, check out my modern physics playlist for more info! The general relativity tutorial in particular. And then also my astronomy playlist for more on black holes.
@@ProfessorDaveExplains Right, I get the warping of spacetime (well mostly) but I figured that is what's happening in a gravitational field anywhere...meaning that I thought the key component to gravity (warping of spacetime) manipulating anything was that whatever that thing is it has to have mass. I've always thought of matter according to its traditional scientific definition: anything that has mass and takes up space. Gravity (warping of spacetime) attracts matter b/c matter has mass. A photon has no mass and essentially doesn't take up space, it isn't really 'matter' by definition, or is it?
To me it suggests that gravity is simply one component / 'side effect' of the warping of spacetime, meaning the warping of spacetime and gravity are NOT exactly the same thing. i.e. there is more to the warping of spacetime than it just creating a gravitational field - it's does more than that I'll check out the videos you mentioned. I think I saw one or two on black holes already.
The black hole is the thing doing the warping, black holes have mass.
@@ProfessorDaveExplains Understood, my confusion lies in that even though the black hole has mass, doesn't anything it attracts have to have mass also? Or is it not required for BOTH objects to have mass?
it's just that the black hole warps spacetime so immensely that the escape velocity exceeds the speed of light, it's all in the astronomy playlist
What is the nature of the electromagnetic field?
Nice explanation sir.... Wow amazing 👌❤️❤️💞👌
Bad news travel faster than than the speed of light.
I love your backgrounds
Nice video, thanks :)
What is the origin of EM spectrum?
Dave fast reply Thanh you. I sent you a response on your quantization part one video. I believe the answer is within Planck constant E=h f .the relationship of capacitance requires permittivity and permeability in free space versus analogy of parallel plate capacitor with quanta units of energy. The math gives h in terms of charge, permittivity, permeability and capacitance. If you want to see the math I can send you a e mail
Thank you sir❤
Watching this enlightened me..😁
Sir, waves are disturbance moving in a medium,ie some energy is transferred through a medium.EM waves can travel through vacuum.Here no medium is distributed.why? please replay satisfactorily
not light! no medium required. it's just the fluctuation in an electric field that is propagated.
Q: Lightspeed is constant in water and in glass and in vacuum, so why not also in Earth’s atmosphere?
And: As lightspeed in Earth atmosphere is constant also when the lightsource is changing velocity,
that should be different for observers when changing velocity?
Or not?
the speed of light is always constant, it just can take light more or less time to travel through different substances because it has to interact with the atoms it contains in order to do so, and that can change the path of the light, so i believe the density of the substance is a factor.
Hi this is a very awesome video. Can we use it for our thesis project?
go for it!
Thank you so much!
Ask the person for money Dave!!
very nice
good video
thanks it helped a lot
This is the best explanation that I have seen or heard. Electro magnetic is good but energy frequency will also cover sound.
What is light?
Light to us is an electromagnetic energy frequency that most living beings translate into what we perceive as light. All other energy frequencies are darkness to us.
If Earth has the only living beings in the Universe and our Sun went supernova extinguishing all life, would the universe be light or dark?
Fat Unicorn other stars dumbass
@@dabmaster1233 it's not about the star, it's about living beings that can translate an energy frequency into what we know as light. The universe would be dark.
Dumbass!
Visible Light would still exist as it is caused by the motion of electrons which would still exist. Being detected or not does not mean they cease to exist.
Evolution has led organisms to be able to detect EM radiation at the ranges most suited to survival given the conditions they exist in.
So it's the other way about. If life ceased to exist then that is all that has happened in a universe which has electromagnetic radiation throughout it.
As light is the electromagnetic field radatiion can manipulating this help with light speed travel?
it wouldn't seem so! check out my four-part series on special relativity, it would require infinite energy to accelerate anything with mass to the speed of light.
Professor Dave Explains thanks very much, i will check it out love your shows keep up the good work
Dave is completely incorrect.
NASA developed an impeller based on photodynamic design--just like an aerodynamic vehicle generates less turbulence with air. Sure enough, the speed of light when measured through this photodynamic architecture was higher than any previous measures of the speed of light, in a vacuum. So, the only way to travel faster than the speed of light is to remove any reference frame by which the speed of light can be measured, and this can be done since light is quantized.
The theory that you cannot design photodynamic vehicles is based on the incorrect assumption that Einstein always assumed was true, the assumption that light can be measured as a classical wave with perfect accuracy. If you check out his paper on the theory of Special Relativity, reading through the introduction where he _assumes_ that the speed of light is a constant at all times, you will see that he (incorrectly) concluded that because any light wave is ubiquitous, any light signal always propagates in every direction simultaneously, and this is simply not the case.
Since light _is_ quantized, there are specific instances where the light of certain frequencies can't exist, because they are unobservable within those spaces, due to the quantized nature of light as described by Maxwell Planck's paper on the topic. Really, check it out:
hyperphysics.phy-astr.gsu.edu/hbase/mod6.html
Unlike classical waves which are infinitely divisible, the quantum nature of light can only be observed in spaces which form harmonic resonance. So if those spaces are offset, or too small for wavelengths of such a size to be observable to begin with, something called the Casimir takes effect:
en.wikipedia.org/wiki/Casimir_effect
The end result of that is a vacuum, with _negative_ energy, a volume of space that has _less_ energy than a 'true' vacuum, and just as you might expect from that information, the speed of light in a negative vacuum is faster than the speed of light in a vacuum, just as how the speed of light in a vacuum is faster than the speed of light in a half-vacuum, which is of course faster than the speed of light in a three-quarters-vacuum.
It's such a simple concept. The speed of light is a constant, but only when it's observable to begin with. This logic just screws with people, because it implies that spacetime can be deleted, which it can be. It's photodynamic.
Super amazing video
My teacher linked this vid ;-;
We have to do a poster about 1 of the 7 electromagnetic waves, I choose ultraviolet.
Thanks professor
David you are awesome!!!
NICE VIDEO
1:18 “What is a kind, Kent?”
here studying the electromagnetic spectrum looking for a connection to consciousness and and all this is connected to the phenomenon
What I still don't understand: How much must be reflected by every object, so that everyone, even people standing really far away can see it? I mean the particles that are reflected must go into every direction and fill the whole space around them to make that possible right? that seems like a crazy amount of waves being emitted by every object and how do these waves not mix with all the other waves/particles that are reflected by all the objects around them?
I'm sure a lot of the waves do interfere and get absorbed but there are trillions and trillions of them everywhere.
@@marksimpson2321 they do, thats why light pollution is a thing
Cross your magnetic n radio waves... Frequency... Is the speed of light?
My physics teacher showed us this 😂😂
Jean-Paul Teitu II, how stupid are you?That comment was from a year ago.
Jean-Paul Teitu II where is your proof of this? You most likely have never met his mother nor has this person met you, so neither of you can objectively call the other stupid with no basis
Okay. I will rephrase it then. How could not see that this was posted a long time before the quarantine, it’s right at the top. My point is how quickly do you read over things that you don’t even pay attention to the big parts. And don’t even try to insult my mom.
@Jean-Paul Teitu II wow I have never seen such rare specimen of ape-human hybrid tell me good sir do you have a brain?
Jean-Paul Teitu II you fucking edited it don’t even give me that shit
thank you sir
Thank you
wtf is that intro lol its AMAZING
I am taking a college level physics, I was told double transverse waves travel through a vacuum at 186,282 miles/s
ya but in the video he said kilo meters
Is there a mathematical connection between light and capacitance in any way??
yikes, i don't know enough about engineering to be able to answer that!
What is different of wavelength of light in water and air?
Wavelength decreases in water and speed slows down. Frequency is the same.
That is the greatest theme song ever. Billy nye just got schooled on theme songs
Wave front?
2:18
Why does all elctromagnetic radiation have the same speed,I mean they should have different speeds because they have differemt frequencues.
"A wave having more frequency travells slower than that of a low frequency wave". Pls explain this🙏🙏🙏🙏
frequency is about number of wave cycles per unit time, all EM radiation still travels at the speed of light
The intro made me subscribe
Thank u sir,
Best stuff ever😉
thanks prof
Thanks for this video. Liked, and added to favorites.
I wonder who or which band sang that opening theme song
band? it's just little old me!
So I was at class writing about how chameleons change their color and now I'm spending recess learning about electromagnetic radiation
Not frequency is wavelength. Unit is nano meter.
You should check the new model, TRICHROMATIC MODEL OF LIGHT COMPOSITION, NOT ONLY OF COLOR.
just entered a red light therapy machine today. Which does have some therapeutic benefits according to scientific studies. The question I have is of the red light therapy machine that is located at my local gym. My question is that, does red light, do you actually see it in the color red or can it still be clear but just immiting at the specific frequency range of red. I ask this because when the machine was turned on I could see the bulbs turns red but as time when by the bulbs seem off white to me. I thought I would be basking in blood red light but apperently not. They gym actually give the kind of bulbs that they use and I didn't take down that information just but I will for further investigation. I mean for it to be therapeutic the light needs to be emiiting within a specific range and so I want to make I'm not wasting my time.
At 2:38, I believe the formula should be c=λf
same thing
@@ProfessorDaveExplains Is there a historical reason for nu instead of f to represent frequency of light, when lowercase f would seem more logical? The letter nu seems like it has no connection to the word frequency.
I always feel free to email you but you are never free to respond me.
Thanks
what an intro!
Wasn't the speed of light in a vaccum was 300,000 m/s? If the speed was 300,000,000 m/s it would only take 30 milliseconds for the sunlight to reach Earth, but as a widely believed fact, it takes 8 minutes and 17 seconds to happen that. Also, as you stated that it takes around a second for light/any electromagnetic wave to travel to the moon, and by considering that moon is around 380,000 meters from earth, it again works out to around 300,000 m/s.
You're confusing kilometres with metres