Introduction to Electrodynamics · Problem 8.16

Electromagnetic Waves — David J. Griffiths

Physics · electromagnetic-momentum

Problem

A sphere of radius

R

carries a uniform polarization

\mathbf{P}

and a uniform magnetization

\mathbf{M}

(not necessarily in the same direction). Find the electromagnetic momentum of this configuration. [Answer:

(4/9)\pi\mu_0 R^3(\mathbf{M} \times \mathbf{P})

]