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.

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

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.

Thank you for the comment!

Awesome!

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@@fufaev-alexander OH yes

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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?

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.

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

Thank for the comment, Samuel!

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.

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…

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

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).

It is the spin of the particles!

yes

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 -.

Yes, this was supposed to be a short video for students to get an initial overview of what distinguishes E and B field.

Wow, clearly I missed the groundbreaking physics conference where they simplified everything down to two cryptic equations.

you're not too dumb, you may just not have the required knowledge to understand it yet

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.

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.

yeah, its a cross product.

@@anupamyedida5484 he assumed it was always perpendicular, thus you get sin90°

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?

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.

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.

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.

Which one? 😁

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.

mri?

@@fufaev-alexander magnetic resonance imaging. Electric or magnetic field?

@@jakubkusmierczak695 What is your guess brother? MAGNETIC resonance imaging?

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.

Because that is the letter someone decided to assign to it a long long time ago. We also use H. H and B.

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.

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.

sure! :D

…what?

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.

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