Question #4be03

1 Answer
Feb 9, 2018

The answer kind of depends on the level you’re working at, but I’ll go ahead and give a simple answer (on d.c. current), leaving you to ask further questions if required.


Electrons are given potential energy (often called electrical energy) as they pass through the cell/power pack and move out from the negative terminal. The electrons move round the circuit, drawn towards the positive (low energy) terminal.

The energy difference between negative and positive terminals is called the potential difference (p.d.) measured in Volts (and is often, though unhelpfully, called voltage.) As the electrons flow round the circuit, they lose their energy in any resistances they meet and it is transferred to heat energy.

The electrons do not however, lose their negative charge - this is an intrinsic part of the electrons - they carry that no matter what their energy. This means that in a simple loop (called a series circuit) there will be the same number of electrons per second passing any point. The flow rate (flow per second) of electrons is called the current, measured in Amps.

In summary: electrons are negatively charged tiny particles that flow to form a current and deliver energy from source (cell) to sink (resistance). Later on, you’ll discover that the charge is tiny thus it takes many millions of electrons to form a measurable current, as a result they actually flow incredibly slowly, but in truly huge numbers.

Thus far, all we have described is the very simplest scenario - one cell, one resistance, in a series circuit, but if you understand these points properly, electricity (one of the most abstract and difficult topics in physics) will never hold any fear for you.