Can you please explain the thing below?
When we add a battery in circuit then, it gives out some electric field that moves through the circuit and gives a force on electrons in conductor to produce current.
When we connect two batteries parallel with each other in a circuit then the electric fields coming out of both batteries moves through the conductor which should give more flux than before. As there is the double number of fields in the same area. But the voltage doesn't double.
What have I done wrong here?
Are there any increasing flux/electric field magnitude when two batteries are connected parallel in a series?
New Edit: I think I have a got three of the very close answers. Let us think about what is going on on the positive terminal and then we will apply the same to the negative terminals just to make it easy to understand.
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"Because the batteries were originally designed for V volts. But on adding batteries in parallel makes a large amount of repulsion in positive terminals that is felt by both batteries and reduces the amount of charge on each terminal which also decreases the voltage of each battery. The total charge of both positive terminals is the same as we get when using battery."
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"But there are people also saying that it depends on concentration of charge not amount of charge"
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"The one another explanation was: first assume that E is the electric field released by each battery, that half of electric field(E/2) from one positive terminal moves toward another positive terminal therefore reducing its half strength and the another half field (E/2) moves in the circuit (not toward the positive terminal) to increase the strength by (E/2), therefore making the total electric in through the resistor = E "
Best Answer
tl;dr Batteries do not create electric fields to move charges. They move charges, which creates electric fields.
This description is, if not completely wrong, at least misleading. A battery is not a source of electric field, it is a source of electric potential. Imagine a battery with terminals in the shape of a pair of parallel conductive plates with an air gap in between (this is a capacitor): as you move the plates toward each other, the field strength (between the plates) increases, and as you pull them apart, the field strength decreases. There is no upper limit to how strong the field can be (well, until it reaches the breakdown voltage and begins to arc), and no lower limit either -- the strength of the field is not determined by the battery. So the battery itself does not directly create an electric field between its terminals.
Moreover, electric field does not "move through" a circuit; charges do. In a simple DC setup like a battery driving current through a resistor, all electric fields are stable over time -- the charges move through the circuit, but the field itself does not. Saying that electric field moves through a circuit is a bit like saying that gravity moves through a rollercoaster. Moving electric fields do come into play with AC circuits and devices with moving parts, such as electric motors; but even a non-moving electric field causes charges to move through a conductor (this is, after all, essentially the definition of "conductor").
So how does current work? Batteries are a source of electric potential, which is measured in volts. Potential is a kind of pressure and in a typical battery this pressure is caused by chemical reactions inside the battery pumping electrons from one terminal (+) to the opposite one (-). The potential difference between the terminals does create an electric field. In the experiment above where the terminals of the battery are parallel flat plates separated by a distance $d$, you could calculate the field strength between them as simply $E = {V \over d}$. But the field is just a way of observing the potential difference between the terminals: it's not the reason the charges are moving in the first place (which is, again, the chemical reactions happening inside the battery).
Pressure is relative, and electric potential is no different. To be strictly accurate, what a battery provides is an electric potential difference ("voltage") between its two terminals. This is basically a measurement of how strong an electron-pump the battery has inside it. This is why connecting two identical batteries in parallel does not add their voltages: because they both provide the same potential difference between the (+) and (-) terminals, there is essentially no difference between two batteries connected in parallel and two isolated, disconnected batteries. The electric potential between the (+) terminals and (-) terminals is the same, and both batteries "agree" on it, so there is no reason for current to flow between them. (Connecting two mismatched batteries in parallel will cause current to flow, in a direction determined by which battery has higher voltage.)
What connecting two batteries in parallel does do is change how the system behaves when under load. If you connect a load, say a 1kΩ resistor, across the terminals of a single 1.5-volt battery, the current through the resistor will be 1.5 mA, all of which is supplied by the same battery. If you connect the same load across the terminals of two 1.5-volt batteries connected in parallel, the current through the resistor will still be 1.5 mA, but now each battery only has to supply 0.75 mA of current. This means that each individual battery is under less load than before, because the electrochemical pumps inside it only have to move half as many electrons to maintain the same voltage. These batteries may last longer and behave better under a variety of loading conditions. (This assumes ideal conditions and perfectly matched batteries. In real-world scenarios, batteries are never perfectly matched, and so you may need a load-balancing circuit to protect the batteries from each other.)