Causality puts certain constraints on the change of the electromagnetic field due to the change in motion of charged particles. Naive calculations of the electromagnetic energy and the work performed by the electromagnetic fields which take these constraints into account might lead to paradoxes involving the apparent nonconservation of energy. A few paradoxes of this type for the simple motion of two charges are presented and resolved in a quantitative way providing deeper insight into various relativistic effects in classical electromagnetic theory.
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