The discussion centers around the determination of the speed of light (c) from Maxwell's equations, exploring the relationships between electric and magnetic fields in electromagnetic waves. Participants seek to understand how c can be derived conceptually and mathematically from these equations, as well as the historical context of measuring the speed of light prior to Maxwell's work.
Participants express various viewpoints regarding the relationship between c, the speed of light, and Maxwell's equations. There is no consensus on whether c was derived to match the speed of light or if it was an independent constant recognized in the context of electromagnetic theory.
Participants reference historical measurements of the speed of light and the development of electromagnetic theory, indicating a complex interplay between empirical observations and theoretical formulations. There are unresolved questions about the nature of c and its derivation from Maxwell's equations.
The displacement current is no current. Its name is from a highly complicated and utterly wrong early mechanical model invented by Maxwell to "derive" is famous equations. Maxwell himself later abandoned all these mechanical models and came to the conclusion that the electromagnetic field is a fundamental entity with no need for any mechanical models.bryanso said:Hi, I hope someone can explain this mystery to me. When we set j to zero, why doesn't the displacement current term also vanish? There is no charge, no current, hence no E field, right?