Confirm that the retarded potentials satisfy the Lorenz gauge condition. [Hint: First sh...

Confirm that the retarded potentials satisfy the Lorenz gauge condition. [Hint: First show that

where ∇ denotes derivatives with respect to r, and ∇′ denotes derivatives with respect to r′. Next, noting that depends on r′ both explicitly and through

, whereas it depends on r only through r, confirm that confirm that

Use this to calculate the divergence of A (Eq. 10.26).]

Equation 10.26