# How does current flow in a short circuit? [duplicate]

In a short circuit, the potential difference across the terminals of a battery (consider a single cell with internal resistance)is 0 according to the equation $$V=E-Ir,$$ where $$r$$ is internal resistance of the cell,$$E$$ is the emf of the cell and $$V$$ is a potential difference across the battery.

If the potential difference across any two points in a circuit is 0, the electric current $$I$$ doesn't flow right? Then how does current flow in a short circuit (assume 0 resistance for short-circuited wire)?

## marked as duplicate by John Rennie, ZeroTheHero, Kyle Kanos, GiorgioP, Jon CusterFeb 28 at 4:22

• Please don't write in all capitals, as that's the equivalent of yelling. Further, you should come up with more descriptive title so that other users can know what you're asking. – Kyle Kanos Feb 27 at 11:20
• Forget the word, "short." It may be useful to talk about a "short circuit" when you are trying to describe a fault condition in some electrical system, but that phrase is not useful when you're analyzing a circuit. It's just a circuit. The circuit that you have described (a practial battery whose terminals are directly connected) can be modeled as an ideal voltage source in parallel with the battery's internal resistance. Now, try asking why current flows... – Solomon Slow Feb 27 at 14:00
• ...But that's an electrical engineering question. If you want to ask a physics question, try asking this: How is it possible for current to flow in a length of superconducting wire when the voltage difference between the two ends of the wire is zero? – Solomon Slow Feb 27 at 14:01

Think about a conventional (idealized) circuit with an ideal voltage source driving current through a resistor. I am sure you agree that current $$I = \frac{U}{R}$$ will flow.