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Physics

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  • $\begingroup$ i did not understand how the electrons get piled up at the junction, if you can provide any reference from any source about such behaviour of electron in any electrical circuit then it would be greatly appreciated. $\endgroup$
    – FUSION X
    Commented May 17 at 18:11
  • $\begingroup$ @FUSIONX this can be seen from Ohm's law. If current density $\mathbf j$ is stationary (steady state of current), and there is a rapid jump in conductivity when crossing junctions A,B, there has to be a jump in electric field at those junctions. Mathematically, Ohm's law says $\mathbf j =\sigma \mathbf E$, so a jump in $\sigma$ has to be cancelled by opposite jump in $\mathbf E$, in order for $\mathbf j$ to not have a jump there. A jump in $\mathbf E$ has to be associated with a non-zero charge accumulation, due to the Gauss law for electric field: $\nabla\cdot\mathbf E = \rho/\epsilon_0$. $\endgroup$
    – Ján Lalinský
    Commented May 17 at 19:49
  • $\begingroup$ @FUSION X I'm going to have to let you down; the 'piling up' was based on intuition. Yet, as you have seen, and as supported by Ján Lalinský's comment, it has to be so. $\endgroup$
    – Philip Wood
    Commented May 18 at 10:46
  • $\begingroup$ I got it.thankyou for the explanation @Ján Lalinský $\endgroup$
    – FUSION X
    Commented May 19 at 17:52