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(This is not a duplicate. I am asking this because I am confused with the potential difference provided by battery and the effect of R(resistance) in in determining the potential difference). Recently in my class I was presented with a $V$ vs $r$ graph where $V$ is the potential and $r$ is the distance travelled in the direction of current while the teacher was teaching Ohm's law [ (Change in potential)$ = IR $]. In the graph potential is shown constant before entering the resistor and while it passes through the resistor it drops by $IR$ and the graph is again constant after the current exits the resistor. It is bugging me for a long time now - how can the potential be constant if current is passing through it. Because I know that current flows in the direction of high potential to low potential and along the path the potential decreases.

potential at point A is constant then on entering the resistance it drops by IR and then potential becomes constant again which is then called point B

john9
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  • It is decreasing so little that you cannot see the slope being different from zero at the scale at which you are drawing it. – naturallyInconsistent Dec 13 '23 at 17:43
  • Help me with this, if there would be no resistor present will no current flow? And also that I know that the potential difference is because of the battery then how does resistance contribute to it? I am just getting everything jumbled up please help me. – john9 Dec 13 '23 at 17:49
  • If the battery is disconnected, no current will flow. If the battery is connected purely by wires, then the wires themselves are the resistance and the entire potential difference will drop over the wires, linearly. – naturallyInconsistent Dec 13 '23 at 17:57
  • I meant to say if there is no resistor then there won't be IR and if there is no IR v(a) will be equal to v(b) which means static condition. – john9 Dec 13 '23 at 17:57
  • Ok I understand this much. But if the battery is already providing the potential difference how is the resistor actually linked with it in the physical sense? – john9 Dec 13 '23 at 18:06
  • Suppose each wire has a resistance of 0.01 ohms. Now re-draw your graph of potential vs position along the path. – The Photon Dec 13 '23 at 18:18
  • And connecting the terminals of a car battery with a wire of 0.01 ohms will result in lots of current flowing until the wire insulation bursts into flames and the wire melts. – Jon Custer Dec 13 '23 at 18:48
  • I already have a very poor understanding in the matter. Can you please tell how the graph would be? – john9 Dec 13 '23 at 18:50
  • Does this answer your question? How electric currents can flow between 2 points at the same potential? – John Rennie Dec 13 '23 at 18:53
  • See, let me explain you what's going on in my mind. I know that the battery is providing the potential difference. So when I connect a wire current flows because of this potential difference which causes an electric field. But I cannot understand how resistance increases the potential difference and here you are saying without much resistance the potential difference is negligible. because I know that it is something which we supply beforehand and then the process takes place. – john9 Dec 13 '23 at 19:24

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