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Is it true that the speed of electrons in the branches is smaller than in the main wire as the current splits in a parallel circuit? If its true, how does the speed reduce (the mechanism, not because of the laws alone)? If not, then what really causes the smaller current in the branches (and the mechanism too).

Kyle Kanos
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Warren
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    A drawing of an example circuit would help, as your question is VERY open-ended. – David White Mar 25 '17 at 15:01
  • This is your first question. Therefore some leniency can be applied. Please be aware that the questions here should be well defined. This is not a guessing game site! – freecharly Mar 25 '17 at 15:26
  • When you ask for the "real reason" for something happening, you are implying that you have been given a reason which you think is false. Have you been given a "false" reason? If not, your use of the word "real" is not appropriate. – sammy gerbil Mar 25 '17 at 16:53
  • Sorry, my English is not good, so maybe using "real reason" is not appropriate. What I meant was that I am asking for the mechanism, not analogy. – Warren Mar 26 '17 at 03:15
  • Related: http://physics.stackexchange.com/q/33621/2451 – Qmechanic Mar 26 '17 at 18:18

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The answer depends on the wires in the branches and the main wire are made out of and what shapes they have. What you can know for sure is that the sum of currents in the branches is the current in the main wire.

Now the current in the wire is the electron charge density times the average speed of the electrons times the cross sectional area of the wire. Now if the wires are made of the same material throughout, the density of electrons is the same, but the current still depends on the cross sectional area and the electron speed. If each branch has half the the area of the main wire, then the electron speed is the same. However, if the branch wires are each as large as the main wire, then the elections in the branch move slower. As a final example, if the branch wires are very thin, the electrons must move very fast to give the same current.

Brian Moths
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  • Thank you, I get what you mean. Sorry that I didn't point out clearly but yes, the branch wires are each as large as the main one. – Warren Mar 26 '17 at 03:29