Why is it so that a charged particle when accelerated radiates energy? I tried to think if it might be violating the law of conservation of energy but the energy transferred by the external agent may simply be absorbed by the electron and it can go on with increasing amount of kinetic energy and it does not need to radiate energy.

There was another question on this website which had an answer that provided an account of this phenomenon in terms of field lines in some inner and outer ring. But, why should we consider field lines? They are merely paths of a charged particle which it will follow when left in an electric field.


One argument: conservation of linear momentum. Something has to take the difference in linear momentum of the accelerated particle.

  • $\begingroup$ Here there is only one charged particle and an external source which is acting on the electron . The linear momentum of the external source as well as that of the electron will remain conserved without the electron radiating . However, if you were saying about the momentum of the electron I doubt it cause it is being acted upon by an external force . Could you make your answer elaborate ? $\endgroup$ – Agnivesh Singh Mar 5 '15 at 4:05
  • $\begingroup$ I need your answer. $\endgroup$ – Agnivesh Singh Mar 7 '15 at 5:27
  • $\begingroup$ @AgniveshSingh no, Agnivesh, the linear momentum is not conserved, I am sorry. If a force acts on the electron, it produces acceleration, by virtue of Newton's 2nd law $F = ma$. $\endgroup$ – Sofia Mar 7 '15 at 10:16
  • $\begingroup$ However, I felt that your answer would lead me to learn about the relation between fields and momentum and hence was eager to understand your answer in detail. $\endgroup$ – Agnivesh Singh Mar 7 '15 at 17:58
  • $\begingroup$ Could we discuss more? $\endgroup$ – Agnivesh Singh Mar 19 '15 at 15:50

Not the answer you're looking for? Browse other questions tagged or ask your own question.