Potential difference and current

[Supernova123]

I have trouble understanding the internal resistance experiment in which potential difference decreases as current increases because I thought they are usually directly proportional to each other. Is there any concept that I am missing? I know that the lost voltage will be greater as current increases but doesn't this apply to other experiments as well? Does the experimental setup have anything to do with it?

 

[sophiecentaur]

I have trouble understanding the internal resistance experiment in which potential difference decreases as current increases because I thought they are usually directly proportional to each other. Is there any concept that I am missing? I know that the lost voltage will be greater as current increases but doesn't this apply to other experiments as well? Does the experimental setup have anything to do with it?

Hi and welcome.
Yes V=IR always. The V in question, however, is the V that is dropped / lost as current goes through the internal resistance - leaving fewer volts, delivered to the battery terminals. The volts lost 'inside' plus the volts across the load (the terminals) will add up to the original battery voltage - or emf, as it's called. The rules apply everywhere and if you draw out the circuit you can see what's happening. Otherwise look at this link.

 

[Supernova123]

I think I understand now. Thanks for your time :)

 

[sophiecentaur]

I think I understand now. Thanks for your time :)

Electricity can be confusing as it sometimes seems counter-intuitive. But you can be sure that it always follows the rules and it will not let you down with a 'but not when there's an R in the month' type of exception. The secret is always to work from what you know towards what you don't know. (More difficult to do than you would think in some cases.)

 

[sardar]

The relationship between potential difference and current is fundamental to understanding the behavior of electrical circuits. While it is true that in most cases, potential difference and current are directly proportional to each other, there are certain situations where this relationship may not hold true. One such situation is in the internal resistance experiment, where the potential difference decreases as the current increases.

This phenomenon can be explained by considering the concept of internal resistance. In any electrical circuit, there is always some amount of resistance present, even in the wires and components themselves. This internal resistance can cause a drop in potential difference, especially at higher currents. This is because as the current increases, more energy is dissipated as heat due to the resistance, resulting in a decrease in the potential difference.

It is important to note that this behavior is not unique to the internal resistance experiment. In other experiments as well, there may be instances where the potential difference decreases as the current increases, depending on the specific setup and components used.

In summary, the concept of internal resistance is crucial in understanding the behavior of potential difference and current in electrical circuits. By taking into account the presence of internal resistance, we can better understand and predict the relationship between these two quantities in various experimental setups.