Question

Why is faraday's law true?
This is something I never found out.

Why do time varying magnetic fields generate electric fields and vice versa?
Is there any qualitative explanation for that?

Answer 1

Like most laws in Physics. Faraday, by carefully observing experimentally the behavior of the a observable cause and effect in particular of induced currents due to changing magnetic flux and postulated the relationship between them.

As for the why of it.?????

Answer 2

By the way the concept of "lines of force" began with Faraday and was eventually accepted and adopted by Maxwell for use in in equations.

Answer 3

Yea I get that.

BUt is there some sort of explanation as to WHY changing magnetic fields must induce electric fields?

Answer 4

It is the nature of charges to induce electric fields as it is the nature of masses to attract one another. Why are there electric charges? The objective of Physics is to explain how things happen. It can identify relationships among various aspects of our universe.

Answer 5

So you are saying that is one of the fundamental things about our universe.
It is like one of the basic rule sets which upon which our universe works. So there is no question to a 'why' it is true.

But we have an answer to why things attract, before we thought even that was a fundamental property, until GR came and gave a reason as the curvature of space-time fabric.

But why charges? That is fundamental atleast that is what I think, because at the most fundamental level, the quarks are all charged. And there is no reason why they shouldn't be, because that is the only way they could interact with one another.
Since at a macro level, it appears to us that matter can have no net charge, we tend to think that matter can have zero charge or it could be charged, and therefore we start questioning why charges exist. But at the micro level we see, that our universe is born with that property.
So are you saying induced fields work the same way? It is one of the facts, and you just cannot ask why?

Answer 6

If I interpret your statement correctly I would say yes It is the nature of charge to behave the way we observe at least as far as I currently understand. It is true by all definitions of the term true. It has never been proven I.e., observed not to be true, at least as far as I know and like conservation of energy it is assumed to be true until it is found not to be so.
Not being able to explain the existence of a phenomena does not make it invalid.

Now whether we can extend our knowledge to relate the behavior of moving charges and changing magnetic fields to more fundamental and unifying descriptions or concepts so we can answer the question why Faraday's Law exists I do not know.

Answer 7

Thank you for your insights gleem!

Answer 8

And thank you for your question. I benefit from thinking about such things and discover the limits of my understanding. It is instructive to discuss more philosophical aspects of Physics sometime rather than the usual operational (computational) aspects as we usually do.

Answer 9

Exactly.. I ll always tag you whenever I have questions like these ;-)