To find the scalar retarded potential, one integrates this quantity evaluated at the retarded time divided by the distance.
In the Lorentz gauge, the inhomogeneous wave equation for phi has a right-hand side consisting of this quantity in the numerator. To find the scalar retarded potential, one integrates this quantity evaluated at the retarded time divided by the distance. In the static case, Jefimenko's equation for the electric field reduces to an integral of this quantity as a function of position. The negative time derivative of this quantity equals the divergence of J according to the current continuity equation. The differential form of Gauss's law sets the divergence of the electric field equal to this quantity divided by epsilon-nought. A triple integral of this quantity gives the total charge in a region. For 10 points, what quantity, typically denoted rho, is the amount of electric charge per unit of volume?
In the Lorentz gauge, the inhomogeneous wave equation for phi has a right-hand side consisting of this quantity in the numerator.
electric charge density [accept rho before "rho"; prompt on "density" a0er "charge"; do not accept or prompt on "density" before "charge"]