tugceerten
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So I don't understand, what exactly is potential difference? + what does it mean to increase it? + why does ac make it easier to increase it?
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Dan_N_2002
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(Original post by tugceerten)
So I don't understand, what exactly is potential difference? + what does it mean to increase it? + why does ac make it easier to increase it?
Potential difference is the work done per unit charge across a component. For charge to flow through a component, work must be done on it (or energy transferred to it at the cell). As the charge flows around the circuit, it loses this energy. You can consider it to not lose energy while flowing through the wires, as well as any voltmeters or ammeters. However, with a component, such as a bulb or resistor, it will lose some of this energy. The potential difference is essentially a measure of the difference between the electrical energy in the circuit at one point and another. The difference is the work that has been done so the charge can flow there. It's important to always talk about potential difference across a component, not through it, since it's just measuring the difference so a PD cannot flow, it doesn't make sense.

Potential difference can be found from the equation V = W/Q, or potential difference = work done/charge. This means 1 volt is the equivalent of 1 Joule of work being done on 1 Coloumb of charge. If you were to increase the potential difference across a component, the work done per Coloumb of charge would have increased, so the energy loss in the circuit would have increased.

Hope this helps.
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Kallisto
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The potential difference consists of the electric field and the charge:

V = E/Q

The electic field in turn depends on the chosen Voltage and the distance of the plates in which the field is working:

E = U/d

Say the charge Q and the Voltage U is constant, increased difference means that the field is stronger, it has to done lesser work to transport the charge from one plate to another because of the small distance between those. In analogous to this a decreased potential difference means that the electrical field is weaker, it has to done more work to transport the same charge between the plates, that has to do with a greater distance of those two.
Last edited by Kallisto; 1 year ago
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Eimmanuel
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(Original post by Dan_N_2002)
Potential difference is the work done per unit charge across a component. For charge to flow through a component, work must be done on it (or energy transferred to it at the cell). As the charge flows around the circuit, it loses this energy. You can consider it to not lose energy while flowing through the wires, as well as any voltmeters or ammeters. However, with a component, such as a bulb or resistor, it will lose some of this energy. The potential difference is essentially a measure of the difference between the electrical energy in the circuit at one point and another. The difference is the work that has been done so the charge can flow there. It's important to always talk about potential difference across a component, not through it, since it's just measuring the difference so a PD cannot flow, it doesn't make sense.

Potential difference can be found from the equation V = W/Q, or potential difference = work done/charge. This means 1 volt is the equivalent of 1 Joule of work being done on 1 Coloumb of charge. If you were to increase the potential difference across a component, the work done per Coloumb of charge would have increased, so the energy loss in the circuit would have increased.

Hope this helps.
"The potential difference is essentially a measure of the difference between the electrical energy in the circuit at one point and another."
A popular sentence in discussing the potential difference that can be found in many textbooks and websites but it is essentially a flaw.

If we look at the unit of the physical quantity of energy difference and the unit of potential difference, they are not the same.

What is electrical energy? Electric potential energy? If it is electric potential energy, you need to realize it involves interaction but the concept of electric potential difference is independent of the interaction. However, electric PD and electric PE are related.

I know it is confusing and that is why a lot of references are not explaining the fundamental differences and the connection between p.d. and PE properly.
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Eimmanuel
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(Original post by Kallisto)
The potential difference consists of the electric field and the charge:

V = E/Q

The electic field in turn depends on the chosen Voltage and the distance of the plates in which the field is working:

E = U/d

Say the charge Q and the Voltage U is constant, increased difference means that the field is stronger, it has to done lesser work to transport the charge from one plate to another because of the small distance between those. In analogous to this a decreased potential difference means that the electrical field is weaker, it has to done more work to transport the same charge between the plates, that has to do with a greater distance of those two.
I would suggest that you get a real physics textbook to study what is the potential difference.

Your very first sentence is already incorrect.
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Kallisto
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(Original post by Eimmanuel)
I would suggest that you get a real physics textbook to study what is the potential difference.

Your very first sentence is already incorrect.
Would be better its in English. Always seem to confuse the terms in this language. Think it is better to get familiar with them.
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Dan_N_2002
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(Original post by Eimmanuel)
"The potential difference is essentially a measure of the difference between the electrical energy in the circuit at one point and another."
A popular sentence in discussing the potential difference that can be found in many textbooks and websites but it is essentially a flaw.

If we look at the unit of the physical quantity of energy difference and the unit of potential difference, they are not the same.

What is electrical energy? Electric potential energy? If it is electric potential energy, you need to realize it involves interaction but the concept of electric potential difference is independent of the interaction. However, electric PD and electric PE are related.

I know it is confusing and that is why a lot of references are not explaining the fundamental differences and the connection between p.d. and PE properly.
Personally I tend not to use the 'difference in electrical energy' explanation if I'm thinking it through or answering questions, but thought it might help explain or visualise the concept. If it's incorrect though, I'll make sure to avoid that in the future.
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Eimmanuel
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(Original post by Dan_N_2002)
Personally I tend not to use the 'difference in electrical energy' explanation if I'm thinking it through or answering questions, but thought it might help explain or visualise the concept. If it's incorrect though, I'll make sure to avoid that in the future.
The way to help in explaining or "visualising" concept is to use correct terms or phrases and should not use things that one avoids in one own reasoning.
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Dan_N_2002
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(Original post by Eimmanuel)
The way to help in explaining or "visualising" concept is to use correct terms or phrases and should not use things that one avoids in one own reasoning.
Hence I'll avoid using that explanation in the future, as I very clearly said.
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