Does the positive terminal of the battery mean that the concentration of electrons is more there. In some places people say that current moves from positive to negative and they call it a convention what does this really mean and others say it flows from negative to positive it's really confusing.
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3$\begingroup$ Why would you think that the concentration of electrons, which are negatively charged, would be at the battery terminal that is positively charged? How does that make sense? $\endgroup$– Bob DCommented Dec 29, 2022 at 14:56
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1$\begingroup$ current goes in the opposite direction of the electrons $\endgroup$– basicsCommented Dec 29, 2022 at 15:25
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$\begingroup$ So does that mean current flows from the negative to positive where charges are concentrated in the negative terminal but in terms with the conventional we identify the negative terminal as positive terminal and visa versa. And I thank everyone for clearing my doubt. $\endgroup$– KP AsksCommented Dec 29, 2022 at 16:14
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$\begingroup$ (a) "So does that mean current flows from the – to +". It's best to avoid "current flows" because it would mean "a flow of charge flows". It's negative charge that flows from the – terminal to the +. (b) "but in terms of the conventional we identify the negative terminal as positive terminal and vice versa" This is very confused. The – terminal is always the – and the +, is always the +. But the convention is to think of positive charge flowing through the external circuit from the + terminal to the –, whereas we now know that in a metal it's negatively charged electrons that flow from – to +. $\endgroup$– Philip WoodCommented Dec 29, 2022 at 19:57
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$\begingroup$ So we assume that it flows from positive terminal to the negative terminal according to convention, whereas in reality in a wire current is from the negative to the positive terminal. $\endgroup$– KP AsksCommented Dec 30, 2022 at 9:37
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The names 'positive' and 'negative' were assigned to charges long before protons and electrons were discovered and even before batteries were invented. The type of charge that glass acquired when rubbed with silk was called 'positive', and the type that amber acquired when rubbed with fur was called 'negative'.
In the early 1800s batteries were invented and found to have opposite charges on their terminals. Hence their designations as 'negative' and 'positive' terminals. When wires were connected across the terminals, heating effects and (in the 1820s) magnetic effects were found and (in conjunction with the running down of the battery) attributed to a flow of charge through the wires. But no-one could know whether it was positive or negative charge or even both that was flowing. [The Hall effect had not been discovered, and few believed that atoms existed, let alone that there was such a thing as atomic structure.] So the decision was made to assume arbitrarily that it was positive charge that flowed through a metal wire from the positive battery terminal to the negative terminal. The 'hand rules' (invented in the later 1800s) that we can use in electromagnetism are based on this so-called conventional current.
In the 1890s, the negatively charged particles that we now call 'electrons' were discovered. [Remember: negatively charged meant having the same kind of charge as amber rubbed with fur!] Within the next few years atomic structure came to be understood as electrons surrounding a nucleus, and electric current in a metal wire, as a flow of electrons. They flow from the negative battery terminal (with an excess of electrons) through the rest of the circuit to the positive terminal (with an electron deficit). Life would have been easier for 20th and 21st century high school students if, back in the 1700s, the decision had been made to call the type of charge that amber acquired when rubbed with fur 'positive'!
answered Dec 29, 2022 at 15:35
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1$\begingroup$ In a metal, we say current is carried by electrons (reality is trickier), but other things (ions, holes, positrons) can carry current, too. Some of these are positively charged. Since the electromagnetic effects of such current are the same, the convention we use is fine: sometimes the flow of carriers is in the same direction as the current, and sometimes it is opposite. $\endgroup$ Commented Dec 29, 2022 at 16:03