7 Differences between Electric and Magnetic Field
HTML-код
- Опубликовано: 22 июн 2022
- • 7 Differences between ...
More: en.fufaev.org/questions/68
Books by Alexander Fufaev:
1) Equations of Physics: Solve EVERY Physics Problem
en.fufaev.org/physics-equatio...
2) Alexander Fufaev and His Never Ending Story:
en.fufaev.org/lifestory
eBook: en.fufaev.org/physics-equations-book
Paperback: tinyurl.com/physics-paperback
Hardcover: tinyurl.com/physics-hardcover
"A Magnetic field, on the other hand, is generated ONLY by moving charges." So all you have to do is move at the same velocity as the charge and the magnetic field mysteriously vanishes, disappearing into the electric field. Because the two are just different parts of the single electromagnetic field, and which parts they each are depends on your frame of reference.
So why are there no monopoles? Why only closed loops for magnetic fields?
Feels like this explanation is insufficient.
@@fenhen From what I’ve been told, theoretically there is no physics that bar a monopole from existing, but we have never observed or been able to create one
Well if we look at this relativistic we cant tell if the electron is moving or not
Total rubbish.
The magnetic field is created by a moving charge. It is nothing to do with the speed of the person observing that magnetic field.
The magnetic field does not collapse because the observer is travelling at the same speed as the electrical charge that created the magnetic field.
Such an assertion would imply that the observer is involved in the creation of the magnetic field and that is just wrong.
This is not quantum mechanics where the observer affects the experiment.
@@kiwi-sw9knThat is not relativity, it is a quantum theory principle.
I don't know how RUclips finds me these little but highly interesting and well researched Videos. 8 Years of German Physics classes couldn't teach me what you did in 2 minutes. Keep it up!
Thank you! Comments like this motivate me to make more video!
Me too! The algorithm shows us what we seek. It can be a beautiful thing. ^.^
5 years of electrical engineering, 4 subjects of physics, plenty of subjects in electrical/electronics engineering, and this is the first time i understand this
One of the best science channels on RUclips. It's pure gold for me as an engineer. Thank You, Herr Alexander!
you're really good at consolidating into the really important things! great work!
As a note, its not actually true that magnetic field lines have to close. (the following discussion is entirely magnetostatic so the field lines are well defined)
This is often called a "textbook error" because it is actually stated in many introductory texts in E&M but is just false. It is possible for B field lines to scatter to infinity (but does require infinite global current and so this is not really interesting). The more interesting case is when they remain contained in a finite volume but never close on themselves. Instead field lines can form an arbitrary aperiodic path within the volume, constantly looping back on themselves but never actually quite returning to the same position and so never closing.
Plasma physicists often call these "chaotic" or "stochastic" fields (they are actually studied with the theory of hamiltonian chaos) and they actually the generic behaviour. A random current density will generally induce a stochastic field. The reason we do not see these configurations in a first course in EM is that all of the configurations of currents you would look at in a textbook have some level of underlying symmetry (infinite line currents, small circular loops, e.t.c). Any continuous symmetry of the current density will reduce the dimensionality of the problem by 1, from a 3D problem to a 2D one where the field lines have to close, so we see closed lines in symmetric configurations but for arbitrary asymmetric ones will see chaotic fields.
Source? This is probably a leap in logic because Gauss's Law says magnetic flux through any closed surface is zero.
I tried to find a source which was open to the public discussing this but could not. There are several academic sources discussing the subject but you need access to journals to read them.
The best full paper on the topic is Hosoda et. al's "Ubiquity of chaotic magnetic-field lines generated by three-dimensionally crossed
wires in modern electric circuits".
A short paper title "The magnetic field lines of a helical coil are not simple loops" is also a good read if you can find it.
Another paper "Realistic examples of chaotic magnetic fields created by wires" is also ok if a bit more concerned with some of the deep dynamical systems theory results which are related.
Regarding gauss's law (or really the no-monopole rule here), it is true that the flux through any closed surface must vanish. But that it not sufficient to require that the field lines actually close. Instead, it only ensures that each field line which enters a surface must also leave it. The formal vanishing of flux adds some technical notes onto this point but they are a bit irrelevant for the discussion here. What matters is that the association of exit points for field lines to the entering partners (which can be on the same actual field line) defines a map from a 2d surface to itself. The requirement that flux is conserved forces this map to be area preserving (this is the technical term) and it is not particularly hard to construct examples of area preserving maps for which points lie on aperiodic trajectories. In fact "almost all" points usually lie on aperiodic trajectories. If a point is on an aperiodic trajectory then what that means is that if we follow a field line which enter the surface at that point then we will observe it enter and exit the surface an infinite number of times but never in the same place twice (or else it would be a periodic trajectory).
This is often called a "naive student error", common among those without a sufficient mathematical background.
All you have to do is follow one of your "hypothetical" field lines repeatedly and get a divergence of B.
Exactly. On my channel you can find a video where I explain an extremely precise algorithm I developed in order to visualize and simulate the magnetic field created by wires in static condition and it's clear that, given a generic system of conductors, magnetic field lines are not closed.
Noo!!.second video and i already love this channel. You got me man. I suscribed
Awesome explanation 👏👏
Very good explanation especially point 6 that's the entire theory behind cyclotron
Thanks!
This makes a lot of things easier to remember!
Thank you for the comment!
Good Information thank you
Thank you so much!!!
Thanks back for the comment!
#### Become a channel member 🏆 ####
As a channel member you have many cool benefits:
* Badge next to your name
* Unique channel emojis
* Your vote counts 10x!
* and much more
ruclips.net/user/universaldenker-physicsjoin
###############
Of course, I would also appreciate a small donation:
tinyurl.com/denker-donate
--------
Top supporters appear here: universaldenker.org/hall-of-fame
...Good night Alexander, I hope you're doing well. If you still have not been able to convince the viewers of your explaining abilities with this presentation, then I am at my wits' end. These videos should definitely be watched certainly by students. If I had had this option in my time at school, it would have saved me a lot of valuable time! Thank you for another great job and well spent time watching your short but powerful video! Take care, Jan-W
I am from India. I get all the concepts very clear from your videos.
Awesome!
I'm so glad I found your channel, you explain things so well. Thank you
Thank you!
Feel free to join the polls I'm doing in the community tab. There you can vote for the next video topic:
ruclips.net/user/universaldenker-physicscommunity
If you like my channel and like my videos, I would be happy about a small donation:
tinyurl.com/denker-donate
Top supporter appear in the Hall of Fame: universaldenker.org/supporter
@@fufaev-alexander OH yes
Wow! This is what people call short and sweet ❤❤❤
What a lovely compitation
The problem is that B in the International Standard ISO, is called Magnetic flux density or Magnetic induction.
The magnetic field intensity is the vector H that measures in A/m . (The electric field measures in V/m )
Thank you so much sir...
Thank you for your feedback!
dude. absolutely fascinating. great content.
however, if I may suggest one thing, number 5. in my opinion, can definitely use more of a deep dive in terms of an explanation.
I'm not naive to physics by any means, however I'm also nowhere near an expert. that's basically why I'm here watching, because I crave new knowledge in the field of all things science. physics in particular.
however, I found myself at the end of number 5 legitimately lost, which doesnt happen very often. dont mean to sound arrogant, though I may not be proficient in every subject in every field, I do have a working knowledge I would say is more robust than your average person when it comes to the content in your videos.
so can you please break down number 5 for me so I can learn something new?? thank you!!!
Thanks for the comment! Difference #5 are units. Do you mean you don't know how the units are obtained?
I'm sorry man, yeah.
what is a volt second? and you say 'in other words, a Tesla'
so a Tesla is the formula you describe. but what is it good for and why do we use it in such terms?
Interesting. Tell me something: about electric field and electric force, who generates who ?
A moving charge is not actually moving, if you're moving right alongside it...
But something like an electron does react to a magnetic field because of its spin, as can be seen in the Stern Gerlach experiment. Are there any electrically charged particles without spin that we know of? Otherwise they would all interact with the magnetic field. They don't interact directly with the magnetic field because of their charge, but maybe indirectly if their spin is somehow caused by or shares a cause with their electric charge.
Yes, you are right. The spin of a charged particle would align in an external magnetic field. I didn't want to push it too far and therefore only considered the "charge" property of a particle.
I understand, probably a good move. But as I understand not only the orientation changes but the trajectory as well, as there are 2 spatially separated sections where the electrons are detected in the SGE detection area.
amazing
Wow!
Isn't this wrong (time: 2:02) "The magnetic field does no work on the charge even when the charge is moving"?
The video is correct. When charged particle in a magnetic field is at rest, it does not experience a force but when it is moving in a magnetic field it experiences a magnetic force (Lorentz force) according to the trajectory of the charged particle. If it is following a straight line parallel or antiparallel to the magnetic field then it will not experience any force. When it is travelling perpendicular to the magnetic field, it will move in a circular path. If it is travelling at any angle other than 0/180/90 degree with respect to magnetic field then it will follow a helical path.
But this force only causes change in the direction of the particle whereas no work is done as there is no change in kinetic energy according to work energy theorem.
@@prajwaljadhav4386 It might be a slip. In the video, a general claim is made as I mentioned above, so, it can be confusing especially for newbies. By the way, in contrary to your comment, changing direction is only possible by exerting force!
As the magnetic field is perpendicular to the director of motion it does not do any work
Remember work = force. dl
As the angle is 90° cos 90°=0
So work is zero
Or other way around as it's a particle it cannot posses potential energy all it has is kinetic energy so the work done by field will go to kinetic energy
and as the force is perpendicular to velocity it changes direction but not magnitude so kinetic energy constant
So no work done by magnetic field
Hope you understand
Faraday cage or a conductor in general blocks an external magnetic field by creating an opposing electric field from conduction charges. Similar things happen with magnetic field in superconductor due to Meissner effect. If electric field can be blocked, can't you block magnetic field with superconductor ?
No this is not correct. Not for a stationary field.
For a stationary magnetic field you need a ferromagnetic material to concentrate the magnetic flux inside it.
Metals such as copper and aluminium, whilst electrical conductors, are not ferromagnetic.
RF energy comprising an electromagnetic photon consisting of a changing electric field and a changing magnetic field pointing in orthogonal directions, then it *is* different.
Don't forget about how electric fields made by time varying magnetic fields forming loops!
This means E = B up to s/m. Everyone understands m/s as speed but what is its inverse seconds per meter? The flow of time in a region of space? I really like thinking deeply about dimensional analysis.
It's similar to how Period (T) is the inverse of Frequency (f), where the former is measured in seconds and the latter in hertz (1/seconds)
So speed describes an amount of distance travelled per a certain amount of time, while this s/m unit would describe the amount of time passed after travelling a certain distance.
@@JakubS this was extremely helpful, thanks.
@@JakubS Like, places where time slows the longer you travel due to gravity or even hypothetical anomalies. Maybe s/m reveals how closely packed occurrences can be across different areas of space. Like a magnetic field where the force is dependent on the speed the vector of the field and the distance between particles, could this somehow tie into extreme environments like black holes? Imagine what s/m values would look like near the event horizon - time stretched to a near standstill…
According to the mathematics behind Maxwell's equations, the E and B fields are roughly equivalent (en.wikipedia.org/wiki/Magnetic_monopole#Duality_transformation). It is the fact that the standard positive particles (i.e. protons, and ionized atoms/molecules) are much heavier than the electron that we see the distinction in everyday life. But this has nothing at all to do with E or B.
Thanks
Thank for the comment, Samuel!
How many differences are there between electric and magnetic fields? All around here you can find videos giving the answer: There is one difference, namely, electric fields exist, magnetic fields don't. Accorduing to these authors, magnetic effects can be explained using nothing more than electric charge and special relativity.
Can you please tell which force is stronger electric or magnetic ?
And why?
In general, the strength of the electric force between charged particles depends on the magnitude of the charges and the distance between them. The electric force follows Coulomb's law.
On the other hand, the strength of the magnetic force between moving charged particles depends on the magnitude of the charges, the speed of the particles, and the angle between their velocity and magnetic field vectors. The magnetic force follows the Lorentz force law.
@@fufaev-alexander but what gives? is it some atomic level magic that makes magnetic fields that much stronger?
If a charge is accelerating/oscillating then an electromagnetic wave (EMW) is produced. The EMW is made of electric and magnetic field. Both of them are in same phase meaning that both attain their max and min values at the same time. The total energy of the EMW is shared equally between both of them
WHAT IF THE DIFFERENCE BETWEEN AN ELECTRIC, MAGNETIC AND ELECTROMAGNETIC FIELD?
PLEASE EXPLAIN
Electric field: exists due to (electric) charges at rest
Magnetic field: exists due to moving charges (electric current) or magnets at rest
Electromagnetic field is mostly referred to waves (either standing or travelling). Electric field energy is passed on to magnetic field energy and then back & this conversion happens & they propagate as a wave (but they're both in phase in free space).
What is a charge?
Charge is the name we give to a property. The property could have been called “attract/repel” or “come here/get away”, but instead it is called a single word “charge”. Just like the property called color has multiple values, red, black, white …, the property called charge only has two values. The two values could have been called any name such as ch or ma (for come here or move away), they decided on the universal opposite symbols everyone knows about, the + and -.
general question: are moving charges causing B in a permanent magnet ?
It is the spin of the particles!
yes
👍
Can a touching of an ark to melaliza power of ALTINATING CURRENT
1:20 Shouldn’t that equation be F = qv X B? (Cross product) Please correct me if I’m wrong
yeah, its a cross product.
@@anupamyedida5484 he assumed it was always perpendicular, thus you get sin90°
E=a=L/T^2; B=f=1/T.
Wow, clearly I missed the groundbreaking physics conference where they simplified everything down to two cryptic equations.
Why is magnetic represented by the letter B?
Because the magnetic field deflects like the letter B. While electric field, E, aborbs. (edit: Jk just some way i remember it.)
😂
That's a smart way to remember it. Thanks,@@BleekersSG !
@@BleekersSG love the way you think
I think it's from Biot-Savart.
differences are very true but the physical difference was not mentioned at all
Yes, this was supposed to be a short video for students to get an initial overview of what distinguishes E and B field.
I thought a magnetic field can be shielded, just like Electrostatic shielding?
A magnetic field can be shielded by the use of a ferromagnetic material which provides a low reluctance for the magnetic field, and the field is concentrated inside the ferromagnetic material.
However, you also need to consider the topic of magnetic saturation.
The electric field is composed of the dielectric field and magnetic field.
This video gives the impression of there beeing no dielectric field.
Explaining the electric or magnetic field without the dielectric field is nearly impossible.
If magnetic field doesn’t work on moving charge, and moving charge generates magnetic field. So does magnetic field won’t work on magnetic field ?
Magnetic fields *DO* influence electric charges. This is how the old style cathode ray tube televisions work.
The force on a charge caused by a magnetic field is determined by the equation:
F = BqVSin(θ)
Where B is the magnetic field strength, q is the magnitude of the charge, V is the velocity of the charge, and θ is the angle of the magnetic field to the charge.
Charged dot not àffected by magnetic field? Am I correctly understand? I'm not native englishman.
It is not true.
Magnetic fields do affect electric charge. Mag fields exert a force on electrical charge, and anyone that says any different is an idiot.
That is how Hall Effect sensors work and old style cathode ray tube televisions.
I'm too dumb for this one but I liked hearing you
you're not too dumb, you may just not have the required knowledge to understand it yet
The fact that the Lorentz Force depends on v, the speed, is "weird" and should trigger any physicist. A force can be proportional to a velocity, but should be a difference between two things, should be "relative" to something else. A force cannot "disappear" by only changing inertial reference. This will eventually lead to the conclusion that electromagnetism is not compatible with classical mechanics, and relativistic mechanics is needed.
Very true. Also when you consider these 'two' fields from this perspective then it is apparent that they are just one in the same. A magnetic field is nothing more than an illusion just in the same way that a gravitational field is an illusion.
If you really look into the math the electric field is just the magnetic field in the time direction.
Ok, but if magnetic fields cant apply work to a charge, how does it accelerates a piece of metal for example?
Good question!
In the case of a piece of meta., It contains free charges (e.g., electrons) that are free to move, the magnetic field can exert a (lorentz) force on these charges. The resulting force can collectively lead to the acceleration of the entire piece of metal if the charges are not restricted in their movement.
@@fufaev-alexander Certainly, this implies that magnetic fields can indeed perform work on charges, doesn't it?
Can an electric field be a closed loop ?
Yes, for example it can be generated by a time-dependent B-field.
If you like my channel and like my videos, I would be happy about a small donation:
tinyurl.com/denker-donate
Top supporter appear in the Hall of Fame: universaldenker.org/supporter
Yes, circularly polarised.
Certainly you should be comparing E and H no?
Technically yes. But in my country, in high school (12th year), we didn't know about D and H. (We were introduced to E and B).
Later in Engineering I realized E and H comes first.
The only difference is a time delay.
Want to produce hydrogen, real simple: When you learn the center field of a magnetic force you won't be doing it that way. First off you need to use the inductive properties of copper in the water in a saw tooth wave form at the correct frequency, not a sign wave. Once you do this you will be on overload with the output of hydrogen. The center field energy from a magnet and the copper inductive field combine to disconnect the two molecules of water!!
MRI? B or E
mri?
@@fufaev-alexander magnetic resonance imaging. Electric or magnetic field?
@@jakubkusmierczak695 What is your guess brother? MAGNETIC resonance imaging?
well, I guess the video is all right... BUT NOW I'M LEFT WITH EVEN MORE QUESTIONS!
Which one? 😁
And why is magnetic field B?
Because that is the letter someone decided to assign to it a long long time ago.
We also use H. H and B.
0:50 this is wrong, in general magnetic field Lines are OPEN as soon as Laplace's formalism is valid. If you struggle to uderstand this fact you can find a video on my channel about this very topic where I simulate generic magnetostatic system with an extremely precise algorithm.
2:00 Is that why an ideal coild doesn't consume active power?
difference 6 is the reason one can run accelerators like for example the CERN ( ...hi Mum!... ), in that the electric field that got inversed the moment the quanta reach it provides for the acceleration every time the quanta pass through, as the magnetic field serves to get them on track that needs to be a circle... ...and I need my life back to ponder the importance and effects on the physiognomy of an atom with respect to electric and magnetic fields, as I stumbled across my thought, that they could turn out way more relevant in the phenomenology of the atoms and therefore of molecules also with regard to chemical reactions ( one electron is off to look for another atom it likes more... ...very very simplisticly spoken.. ) than one has been thinking hitherto.
And I think to look, if I am able to come up with something like an alinear version of the schrödigner-equation might be an inception, to get this on a regular mathematical base.
Le p'tit Daniel, who needs to look for other bases with respect to base-jumping for this is off due to his medical record...
1:55 That does not sound correct.
If the motion of a charge carrier is parallel to the magnetic field, no force is exerted. However, if the motion of a charge carrier is perpendicular to the magnetic field, a force is generated. Otherwise, electric motors would not operate.
Force perpendicular to motion does no work. Just because a force is present doesn't mean work is being done.
@@tavobenne If the summed up force on an object is greater then zero, there is an acceleration.
A force perpendicular to motion pushes the object to do a curve.
@@dark_knight2357 Yes... I know... but that won't do work. For work to occur the force has to have a component which is parallel to the objects motion.
Read work energy theorem, the kinetic energy of the charge remains constant in a magnetic field, that is why magnetic force is a no work force. And W=FScostheta
@@ranjitmondal2374 I apologize for any confusion. As a non-native English speaker, I misunderstood the difference between "no work is done" and "no force is induced". In reality, when an object changes direction, no work is done on it, but a force is still induced to make the change. Therefore, the object's kinetic energy remains the same, but its direction is altered.
N and S mag fields are part of a vortex of Aether one cannot exist without the other….
sure! :D
…what?
"The magnetic field does no work on the charge even when it's moving": Not parallelly but yes transversely.
"A magnetic field cannot be shielded": Oh yes it can, by redirection.
The magnetic field does do work on the charge, it fundamentally does.
The magnetic field exerts a force on charged particles.
That is how Hall Effect sensors work and old style cathode ray tube televisions.
Anyone claiming that a magnetic field has no effect on an electron is a complete and total idiot and you should seriously question their level of knowledge and how well qualified they are in the topic.
@deang5622 not doing work and not doing anything are two very distinct concepts. Magnetic forces do no work because the force vector is always perpendicular to displacement, which by definition makes work zero. This means that magnetic forces cannot change the total energy of a particle but they can still change the direction of the velocity vector for example. In pretty much all cases where the magnetic forces seem to be doing work, you generally find that some sort of electric force is responsible for any change in energy.
Wtf
E🆚 🅱️
You don't explain things that well.
Thank you!
@@fufaev-alexander You need to explain for example why magnetic fields do no work even when particles are moving. Something moves, therefore has kinetic energy, yet, no work is produced by what's moving it. 🤔
A paradox.
@@TheAtheist22 He doesn't mention it here, but the force experienced by a charge in a magnetic field is the cross product of the charge's velocity and the magnetic field, multiplied by scalar q.
Because the force is the cross product of v and B, the resulting force vector is perpendicular to both. Since the force is perpendicular to the velocity at all times, the work done is zero.
Thanks
Thank you for the donation!