I was just wondering what happens in a circuit in terms of different types of energy transformations. If you apply a voltage to a circuit then electrons start moving (very slowly). Since the electrons want to flow to the positive terminal they will have electrical potential. But the electrons are also now moving once the voltage is applied as there is a current so would they have kinetic energy as well?
Some information I have found online says that electrons collide with atoms in a bulb and this is why the filament heats up. But this would imply that kinetic energy is being transformed into heat and this can't be correct because surely any change in kinetic energy would alter the current flowing? Also, in a series circuit, if you measure the potential difference between any 2 points after all of the loads then you always get zero. I was just wondering why it is zero because don't the electrons keep moving even after passing through all the load in order to get back to the power source so surely they cannot do this without some form of energy?
Best Answer
You can think of this just like gravity. See below.
Voltage is a name for electrical potential difference.
Yes.
Yes.
It does alter the current flowing. Without the resistance, the current would be much, much higher.
The end-result is indeed a slower flow, i.e. a lower current, than without this resistor present (in that particular part of the circuit).
Remember Newton's 1st law. If charges exit the last resistor, they are no longer slowed further down, no. But the speed they came out with will stay. If nothing prevents them along the wire alone, they will not speed up, no, but also not slow down. So they continue.
And should one be stopped by whatever reason, the next charge will come and push it forward (like-charges repel). This is the case when the wire is not a completely perfect conductor but has a little resistance.