Assignment 1, Question 11

[Shubharup Ganguly]

It asks for direction of positive current. 

a) What is the direction of current as is normally understood - flow from region of high potential to region of low potential, or opposite to the direction of flow of negative charge?

b) Does positive current mean just regular current, or the direction opposite to that?

[swarnab.d...@gmail.com]

The direction of current across a potential difference(in this case, the cell membrane) is conventionally taken to be from higher potential to lower potential i.e. the natural direction of flow of positive charges or the opposite direction of the natural flow of negative charges. This is also called the direction of positive current. Since the inside of a cell membrane is at a lower potential than the outside, the direction of current or positive current would constitute the flow of positive charges(na and ca cations) from the outside to the inside and the flow of anions from the inside to the outside.