Phys 200C – HW6

Due Wednesday -May-04 noon to Daniel Cebra’s Mailbox (Graded by: Daniel Hale)

6-1. In terms of the 4-vector potential, what is the field strength tensor F_mn?

In terms of the electric and magnetic fields, what are the elements of F_mn?

In terms of the electric and magnetic fields, what is the lagrangian density for the free E&M field?

Is the Lagrangian a Lorentz scalar field?

How can you easily justify your answer?

It is often said that magnetic fields are a consequence of electric fields and relativity. Suppose that in some frame E = 0 everywhere but B is not zero. Is there a frame in which E’ is not zero and B’ = 0?

6-2. Problem 12.14 in Jackson.