If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

### Course: Class 10 Physics (India)>Unit 3

Lesson 2: Electric potential & potential difference

# Intro to potential difference (& voltage)

Let's understand the concept of voltage intuitively.  Created by Mahesh Shenoy.

## Want to join the conversation?

• For creating the electric current motion, you explained that positive terminal of the batery pushes the charges away from them, and the negative terminal of the battery pulls towards it. I understand that, but what if instead of having a negative terminal we have another positive terminal but "more positive"?
I think will still have a potencial difference because the charges of the terminals will be different,but, will both positive terminals push the positives charges away from them? (sorry for my bad english)
• considering that there are two like terminals at the same battery, any one of the two possibilities could occur:

The battery will itself not work considering that both the poles will push away the electrons

there will be an extreme concentration of electrons in one particular region of the conductor.
• Why is potential difference required for the flow of charges?. Why did the speaker say"we will get the continuous flow of charges if we are able to maintain potential difference in the either sides of wires". Please justify.
• U can consider the battery as a pump. The pump takes( pushes) the water from the ground to a higher level above the ground. The water can't go by itself to higher level. So the pump does work to take (push)it to the higher level. But u see that if water is allowed to flow, it can flow by itself to the lower level because it's the natural tendency of every thing. Here the gravity takes it down (pulls it). Now if the pipe which contains water has both ends at the same level there is no water flow Cox both points are at the same potential, there is no force acting to pull or push it.
• why do we assume that near the positive terminal of a cell it has positive charge?
• In a cell due to the chemical reactions that happen inside ,electrons will be excess over the negative terminal .This excessive charge over the negative terminal makes the positive terminal positively charged. This charge difference in the positive and negative terminal causes potential difference that causes the flow of electrons
• Can there be potential difference in the wire if the charges just move through the wire without being connected to any external devices?
If no, will the charge gain potential again after moving through the circuit and reach the negative terminal of battery and get out with double potential from positive terminal?
• If a battery is connected to a wire on both terminals with no external devices, there will still be a potential difference and the current will flow through the wire. From what I understood, heat will be generated in the battery itself and it may catch fire and/or explode.
You can search more about the mechanism if you want.
• The current flows from a region of high potential to a region of low potential.As a electron flows through the bulb it does some work and hence potential at the negative side of the bulb must be more. But this means that current flows from a region of low potential to high potential.
(P.S - Potential at a point is the work done in a unit charge from infinity to that point.)
(1 vote)
• Hey there,
Potential at a point is the work done in a unit charge from infinity to that point
Tiny basic gone wrong pal,
potential at a point is the potential to do the work, here work isn't already done.
for example, let's go back to the slide scenario---the kid at the top has more potential or more capability to do work (he hasn't done any work yet) when compared to the the child at the bottom who has already done work
similarly, the potential at the +ve terminal has more potential to do work (that is why the bulb lights up)
it's similar to you having more energy after eating food, after you eat you have the potential to do more work(consider running....not a great idea ideally but I hope you get what I mean) than after an intense workout.
I'll let you connect the dots
Remember Current is the same throughout the circuit, only the potential to do work by each charge changes as it moves between the terminals.
Hope this helps,
if I'm wrong do let me know (this is just on my understanding of the concept)
• Why the bulb gets hot and why the charges didn't loose potential all the way until it reached the bulb?
• The filament of the bulb is very thin, hence has good resistance . This turns the electrical energy into heat.
(1 vote)
• What causes those particles to lose their potential energy at the bulb?
• The particles contain potential energy. When they move through the bulb, friction converts that potential energy into heat. The heat is released and the particles lose their potential energy.
• doesn't current flow from the negative terminal to the positive terminal?
• Yes, but it is taken to be moving from the positive to the negative as per the convention. Before electrons were discovered they were considered to be positive entities so till date (even though we have discovered them carrying negative charge) we consider the current to be flowing from positive to negative.
(1 vote)
• During the loss of potential energy by the charge, because of the bulb, is all the potential energy lost or only some amount of it?