Why does a moving charge create magnetic field

This is response of H C Verma to this question asked by a class 10 student

[prakharvishwakarma]

Despite being the most popular author you are so kind and humble.

[inexorableshriyank]

Autocorrect: 99.9% of this are watching this without searching for this topic or channel
Salute to him

[nameyettobedecided]

the guy who questioned: Thats exactly how everyone reversed my question.

[ArnabBose]

This is a very nice question! The best explanation I know comes from Feynman, with a thought experiment that shows magnetic force is just electric force in a different frame of reference. Allow me to explain.

Imagine a wire conducting electricity. Since it has a current, electrons are moving through it in one direction. And since the wire itself is neutral, if you take any segment of the wire at any instant, there will be equal number of electrons and protons in it (with the protons being static, and electrons zipping by).

Now suppose another positive charge is moving along side the wire, very close to it, when the same speed as the electrons. If we change the frame of reference to move with the speed of the electrons, we see the new charge is static, as are the electrons. But the protons are zipping by in the opposite direction. Due to special relativity, and lorenz contraction, the distance between the protons will reduce. From this perspective, the density of protons will no longer be equal to the density of electrons in the wire, resulting a net positive charge field around the wire - so our new positive charge will experience a push.

The magnetic force is precisely a way to express this force in the original frame of reference, where the new charge and electrons are in motion. There the moving electrons give rise to a magnetic field, which is felt by the positive charge as it's moving, perpendicular to it's motion and direction of the magnetic force leading it away from the wire - resulting in same set of events.

[sanket]

Others in lockdown - Tiktok vs YouTube
HC Verma - why does a moving charge create a magnetic field ??

[Sagar-fosk]

90% of students are watching this without searching
Edit:
Thanks for 3+k likes
2nd edit : moral of my comment is : to get like in comment do smart work not hard work😎😎😎

[abhishekgarg]

Thanks Sir.
Just to summarize :
1) A static charge has the property that it produces Electric Field.
2) A charge when moving at uniform velocity has the property that it produces Magnetic Field.
3) A charge when moving under accelerated motion or is under an oscillatory motion, it generates time varying / oscillating coupled Electric Field and Magnetic Field which we call as Energy propagating in space i.e. Electromagnetic waves.

[arushimittal]

He is so humble..that's exactly how a person should be!!

[rit]

I cannot understand how the best Physics influencer in India can be so down to earth? Hats off sir!

[braaaaaja]

Q. Why does moving charge creates magnetic field?

A. You will get to know after 4 - 5 years of study in special relativity.

[Adityarm.]

This was actually on-point. Couldn't have stated it better. It makes me happy when students question the founding assumptions - these lead to deeper insights into how physics as a field of study works regardless of whether the question can be answered [for example, by pointing to a deeper layer] or remains unanswered [for the currently accepted true foundations of physics].

[shivanisoni]

Sir, I had the same query since 5 days, and was trying to find the answer. And I found it❤️. With Great Respect.🙏

[VizzLit]

I never knew he also had his youtube channel....getting answer from the legend itself lol

[KumarAcademy]

Sir does running fan at 4 speed and at 1 speed makes any difference on electricity bill ?

[fallen]

As far as my thinking goes I think that the electric and magnetic field induced by a moving particle are the same phenomenon viewed by different frames of reference. Think of it like this "you are negatively charged and hence are being pushed away from the particle that too happens to be negatively charged so from your pov you are being repelled because of the charge and someone else looking at you from their respective pov might think that you are being pushed away because of the magnetic field" let's suppose that you are stationary so it may seem to someone that you are not at all affected by the fields...this was the best explanation I could come up with...🙌🙌

[alokjha]

Wonderful to hear from the legend. 😊. Sometimes I believe it gets confusing for beginner physics students as we usually learn about magnetic and electric field as a separate phenomenon and then come to know about their unification. However, its understandable as it might get difficult if we start explaining complex things first i.e special relativity and lorentz transformations.

For simplicity, both electric and magnetic field are actually the same thing viewed differently in different frames of reference.
Even a stationary charge will produce a magnetic field if we are moving w.r.t to it. What we perceived as electric field in one frame will be perceived as magnetic field in another frame of reference.

But again, to understand these concepts clearly, we will have to abandon the newtonian mechanics that is so much rooted to our understanding that relativistic mechanics appears baffling to our minds.

[rahulnainwal]

The guy who asked the question is still perplexed 😅😂.

[jamestrujillo]

Every single video, he always smiles. What a great teacher. I've also learned physics from so many of his videos

[Physicswithshivam-od]

Sir I am really shocked to see such a popular man ; with such humbleness. Hats off to you ! I bow down before you

[PraveenKumarFC]

In an atom the electrons moving revolve around the nucleus so it accelerated and according to the maxwell theory of electromagnetic radiation every accelerated charged particles releases both electric field and magnetic field which are perpendicular in direction of oscillation but same along the direction of propagation. I think its clear ♥♥