Definition of current

[Hemichordate]

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So this has been bugging me for a while, and it popped up on one of the AAMC practice tests:

So current flows from positive to negative, correct? Even though we know that the flow of electrons which generates current flows from negative to positive.

 

[crazybob]

current is the flow of hypothetical positive charges. so if an electron flows from left to right, the current flows from right to left.

 

[boaz]

This convention exists because before the discovery of the electron it was thought that it is the positive charge that moves. It's kinda confusing, but I guess it was so entrenched in physics that it just stayed that way for convenience. Although physically it is the negative charge that moves, when we work problems the result is the same even though we think of the positive charge as moving.

 

[Hemichordate]

So then if an electron was emitted from the positive end, why is it still called current if current is defined as the movement of positive charges?

 

[wanderer]

So then if an electron was emitted from the positive end, why is it still called current if current is defined as the movement of positive charges?

A more precise statement would be, "The direction of current is the direction in which positive charges flow."

 

[ezsanche]

So then if an electron was emitted from the positive end, why is it still called current if current is defined as the movement of positive charges?

the electron is being emitted from the negative terminal not the positive terminal.

 

[crazybob]

So then if an electron was emitted from the positive end, why is it still called current if current is defined as the movement of positive charges?

http://en.wikipedia.org/wiki/Electric_current

and electrons would flow from the negative terminal to the positive terminal. because the negative end has more electrons than the positive end.

 

[Hemichordate]

http://en.wikipedia.org/wiki/Electric_current

and electrons would flow from the negative terminal to the positive terminal. because the negative end has more electrons than the positive end.

Well yes I know that. The question asked "what if an electron was ejected from the cathode", so wouldn't that be the same situation?

 

[ezsanche]

Well yes I know that. The question asked "what if an electron was ejected from the cathode", so wouldn't that be the same situation?

The current is always opposite of the to the movement of the electron. t