# E&M question

1. Apr 18, 2012

### Miviato

1. The problem statement, all variables and given/known data
Can you derive Maxwell's equations from conservation of charge, energy and angular momentum for E&M fields?

2. Relevant equations

3. The attempt at a solution

2. Apr 18, 2012

### sunjin09

Once you are able to define these quantities, including EM fields themselves, I'm sure you can. But without Maxwell's equations, how do you even define a charge?

3. Apr 18, 2012

### Mindscrape

One could argue that the field theory approach, deriving Maxwell's equations from the Lagrangian with 4-vector potentials, is what you've asked about.