Today's Learning

I was looking at a lot of YouTube videos today that would give me me clue to what electromagnetism is, how it behaves and why it exists.

For the first two questions I was able to get some reasonable explanations, but for the why, well .. lets say it was pretty fuzzy.

In the process, I got to brush up on the basic laws of electricity that we learn at school and I should say, though they made sense, it still sounds like voo-doo sometimes.

Now I am clear on:

The left hand rule that gives the direction on the magnetic field that would be generated by flowing Electrons. Where the thumb points to direction of flow of electron, the fingers would point to the direction of field lines of the magnetic field.

The right hand rule is the same, but is used for positive charge flow direction or the conventional current direction.

Oersted was the guy who first discovered that flowing electrons generate a magnetic field.

The same left hand rule can be used to find the direction of the N pole that would be generated inside a solenoid, except in reverse. That is, if the curved fingers pointed in the direction of flow of electrons, the thumb would point to direction of the N pole! Isn't that simple!

Another thing I learnt today was that Ampere discovered that two wires carrying current in the same direction would attract each other. Here is a fantastic video that makes it all clear.

Also the thing to note is that if a magnetic line of force is say, pointed towards the right, the north pole of a compass will also point to the north. This is the first time I see a circular magnetic field, and here is a video that clear shows that.

Apart from that I also recalled how a battery works, How but not yet Why deeply enough, that's why I am going from the basics. And here is nice cool video that shows how a car battery works.

I also saw how the electron was discovered by J J Thompson, and then how the atom model was given by Rutherford. Here is a nice video for that. And then I saw how the idea of electricity as a invisible fluid that present in all matter is the reason why so many of the terms that are used to describe electricity are like current, charge (yes even that!), flow from positive to negative and the like. And, you guessed it, here is the video.

Last but not the least, I also saw the Faraday's law of electro-magnetic induction. Which is that a changing magnetic field also generates an Induced current is nearby conductor not only the other way around as was previously believed. That is something extraordinary to come up with really. But I am not clear on why that happens at an atomic level, and I am told that its basically quantum-electro-dynamics as explained by the likes of Feynman. Cuz intuitively it doesn't make sense that an electron, an electric charge would be affected by a magnetic field and then start flowing!!!

The unified theory of strong and weak electromagnetic forces was something cool look at. The video is at the same place where the Rutherford's story was shown.

Oh and there was also this video that said that the reason for the magnetism generated by flowing electrons was their spin. When electrons flow they are all somehow spinning in the same direction, just like in natural magnets, causing a magnetic field. At first glance it makes sense, but something doesn't fit here. Like, is there a polarity of charge even on an electron?If so, then the electron is not the basic elementary charge, the charge is actually sitting on an electron. Then what makes up charge? Is there a relation between where the charge is on an electron and how the electron is spinning? Cuz only if that relation is same, will all electrons be spinning uniformly.

But here are the questions:

First off, why is the measure of force of a magnetic field on an unit charge taken as the basis for calculating magnetic field strenght. F = BqvsinTheta or F = BIlsinTheta is a famous formula, used to calculate B in terms of Ns/Cm or Tesla. But Why oh why would they take a electric charge as the basis for magnetism? Is it cause of its almost non existent weigth (in case of an electron)?

Like charges repel, unlike charges attract. Agreed. But why does an electrical property of a particle or matter, result in the physical motion or manifestation? There are lot of purely physical forces like, angular momentum that a fundamental, electricity cannot explain them, hell they cause a lot of things to happen in the electric realm. Why are there some physical forces that cannot be explained by electricity, but physical forces like attraction or repulsion ie physical movement is explained by it. Basically, why would electric property of a body make it to react physically. The chemical composition doesn't make it happen, that too is at atomic level then why this?

Third is why does a wave move or propagate? As I understand, the vibrating electric charges cause a field to radiate. That doesn't tell me anything. The charges are in their place, they are vibrating on the same spot, their field of influence is limited, we all know that, then why does a fluctuating field of influence propagate?

Last but not the least, I repeatedly hear that electricity and magnetism are two aspects of the same physical phenomenon, without any clue to what that 'phenomenon' actually is.

Answer soon I hope.