When an electric current is passed, electrons move from (a) High potential to low potential. (b) Low potential to high potential. (c) Electrons flow from lower to higher potential except through power sources. (d) Electrons flow from higher to lower potential, except through power sources

The correct statement is (d) "Electrons flow from higher to lower potential, except through power sources."

In an electric circuit, when a potential difference (voltage) is applied across a conductor, an electric field is established within the conductor. This electric field exerts a force on the free electrons present in the conductor, causing them to move. Electrons, which are negatively charged, tend to flow from areas of higher electric potential (higher voltage) to areas of lower electric potential (lower voltage).

So, when an electric current is passed through a circuit, electrons flow from a region of higher electric potential (higher voltage) to a region of lower electric potential (lower voltage). This flow of electrons constitutes the electric current.

However, it's important to note that power sources (such as batteries or generators) can create a potential difference that causes electrons to flow in the opposite direction, from lower potential to higher potential, within the circuit. This is because power sources work by converting some form of energy (chemical, mechanical, etc.) into electrical energy, effectively "pushing" the electrons in the opposite direction to their natural flow.