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When charge moves at a constant speed, it is said that it produces static magnetic and electric field.

Why static ? If it moves, at every points, electric field and magnetic field change as they are dependent on a distance to the point. So even if charge moves at constant speed, we still should have electric and magnetic fields changing in every point in space.

2 Answers2

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Indeed, neither the electric nor the magnetic fields are static in the case of a charge moving with constant velocity. However, the fields, although they are not static, they also do not radiate.

Dale
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Change does not mean radiation, to get radiation a necessary condition is that the field components vary as $\mathcal O(r^{-1})$, Then $S=E\times B$ will be $\mathcal O(r^{-2})$ which will give a nonzero value when multiplied by $4\pi r^2$, a surface area far away. This cannot happen if there is no work done on the source, see, energy conservation. A charge moving with a constant velocity all by itself is neither doing work nor having work done on.

hyportnex
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