Question

Why electric charge moves from high potential to low potential?

Answer 1

An electric current is defined to be the movement of positive charges(This is a rather unfortunate convention if I may add). In reality, it is the electrons that do the moving. This happens because , an electric field appears inside conductors when when you complete the circuit. The electrons, in good conductors, are nearly free and begin to move under the influence of the electric field, from lower potential to higher potential. The “current” , by convention, therefore “moves” from higher potential to lower potential.

Why then do electrons move from lower to higher potential? This is, unfortunately, also a matter of definition. Maxwells equations(In the static limit) allow us to write E⃗ =−∇⃗ V.E→=−∇→V.The force experienced by the electron is therefore: F⃗ =−eE⃗ =e∇V.F→=−eE→=e∇V. Hence, the force experienced by an electron is always “along” the direction of the gradient, from lower potential to higher. Since electrons always move locally to higher potentials, they must, also move globally to higher potentials.

Hope this helps.