Understanding the Relationship between Work and Volts

In summary, the conversation discusses the concept of work having units of volts and how this may be confusing. It is clarified that work and voltage are not equivalent and that one volt is equal to one joule of energy per coulomb. The conversation also mentions the use of "volts" for shorthand instead of "electron volts" and the importance of including charge in units of coulomb-meters.
  • #1
jeff1evesque
312
0
Question
I was wondering how the concept of work can have units of volts? I mean work has the units of N/m = J =/ J/(A*S) = Volts? Yet I am reading they are equal? Can someone enlighten me?
 
Physics news on Phys.org
  • #2
Can you check your units? [E]=[F][L] which is energy = force * distance. You're saying energy/(current*time) = volts on the right side which is dimensionally correct but were you meaning to equate the two equations? Particularly what do you mean by "I mean work has the units of N/m = J =/ J/(A*S) = Volts" ? Do you mean =/= which is not equal to or do you mean possibly 1/J/(A*s) which is equal to A*s/J?
 
  • #3
jeff1evesque said:
Question
I was wondering how the concept of work can have units of volts? I mean work has the units of N/m = J =/ J/(A*S) = Volts? Yet I am reading they are equal? Can someone enlighten me?
This statement is wrong.
Work = Nm
 
  • #4
Pengwuino said:
Can you check your units? [E]=[F][L] which is energy = force * distance. You're saying energy/(current*time) = volts on the right side which is dimensionally correct but were you meaning to equate the two equations? Particularly what do you mean by "I mean work has the units of N/m = J =/ J/(A*S) = Volts" ? Do you mean =/= which is not equal to or do you mean possibly 1/J/(A*s) which is equal to A*s/J?

What I meant was: Nm = J =/= J/(A*S) = Volts
 
  • #5
jeff1evesque said:
What I meant was: Nm = J =/= J/(A*S) = Volts

Well that certainly is true... what seems to be the situation? Joules is definitely not going to be equivalent to Joules divided by charge (that is, current * time).
 
  • #6
Pengwuino said:
Well that certainly is true... what seems to be the situation? Joules is definitely not going to be equivalent to Joules divided by charge (that is, current * time).

Note: [tex]\hat{E} = - \frac{V_0}{d}\hat{z}[/tex] (volts/meter) is the electric field between a capacitor, and V_0 is the potential difference in a power supply for a circuit.

Then the following statement (from my notes) is not correct?

Work

= [tex] \int_{bottom}^{Top} \frac{\hat{F}}{Q} \bullet \hat{dl} \equiv potential-difference = \int_{bottom}^{Top} \hat{E} \bullet \hat{dl} = \int_{bottom}^{Top} - \frac{V_{0}}{d}(\hat{z} \bullet \hat{dl}) = -\int_{bottom}^{Top} \frac{V_0}{d}dz = -V_0 (Voltz)[/tex]

thanks,Jeff
 
Last edited:
  • #7
I may see the source of confusion. Sometimes physicists will express energy in terms of electron volts, eV. One electron volt is the work done on an electron subject to a changing of one volt in potential. It has units [Q][V].

In some discussion one might simply say "volts" used in place of "electron volts." It saves 3 syllables out of 4 in short-hand discourse.
 
Last edited:
  • #8
Phrak said:
I may see the source of confusion. Sometimes physicists will express energy in terms of electron volts, eV. One electron volt is the work done on an electron subject to a changing of one volt in potential. It has units [Q][V].

In some discussion one might simply say "volts" used in place of "electron volts." It saves 3 syllables out of 4 in short-hand discourse.

Very cool to know. Thanks a lot.

JL
 
  • #9
jeff1evesque said:
Then the following statement (from my notes) is not correct?

Work

= [tex] \int_{bottom}^{Top} \frac{\hat{F}}{Q} \bullet \hat{dl} \equiv potential-difference = \int_{bottom}^{Top} \hat{E} \bullet \hat{dl} = \int_{bottom}^{Top} - \frac{V_{0}}{d}(\hat{z} \bullet \hat{dl}) = -\int_{bottom}^{Top} \frac{V_0}{d}dz = -V_0 (Voltz)[/tex]
No, it's not correct. Everything you wrote out in LaTeX code (from [itex]\int \hat{F}/Q\cdot\mathrm{d}\hat{l}[/itex] onward) is right, but it's equal to voltage, not work.
 
  • #10
I can't speak about your notes, but maybe a conceptual explanation would help? For example, if a particle with charge 1 Coulomb, initially at rest, was released to move through a potential difference of 1 Volt, after that time the particle would have 1 Joule of kinetic energy. The volt is energy per charge. In the same way, if you had to perform 1 Joule of mechanical work to move that 1-Coulomb particle slowly through an electric field, you would have moved it through a potential difference of 1 Volt.
 
Last edited:
  • #11
Voltage is equivalent to work done per unit charge. This is not the same thing as work.

In SI units, Volts are equivalent to Joules/Coulomb.
 
  • #12
Phrak said:
I may see the source of confusion. Sometimes physicists will express energy in terms of electron volts, eV. One electron volt is the work done on an electron subject to a changing of one volt in potential. It has units [Q][V].

In some discussion one might simply say "volts" used in place of "electron volts." It saves 3 syllables out of 4 in short-hand discourse.

You were right, I talked to my teacher today, and he said it's basically what he meant, Quolomb*meters.

Thanks,


Jeff
 
  • #13
jeff1evesque said:
You were right, I talked to my teacher today, and he said it's basically what he meant, Quolomb*meters.

Odd. He left the charge out of Coulomb-meters?
 

1. What is the relationship between work and volts?

The relationship between work and volts is that work is the product of the electric potential difference (volts) and the amount of charge (coulombs) that moves through a circuit. In other words, work is equal to the product of volts and coulombs.

2. How does voltage affect the amount of work done?

Voltage plays a crucial role in determining the amount of work done in an electrical circuit. As voltage increases, the amount of work done also increases, assuming the same amount of charge is moving through the circuit. This is because voltage is a measure of the electric potential difference, which is the force that drives the flow of charge and ultimately determines the amount of work done.

3. Can work be done without voltage?

No, work cannot be done without voltage. Voltage is necessary to create an electric potential difference, which is the driving force for the flow of charge and the basis for the concept of work in electrical systems. Without voltage, there would be no energy transfer and therefore no work done.

4. How does work affect the voltage in a circuit?

Work does not directly affect voltage in a circuit. Instead, it is voltage that affects the amount of work done. This is because voltage is a measure of the electric potential difference, which is the force that drives the flow of charge and ultimately determines the amount of work done.

5. Is there a limit to the amount of work that can be done with a specific voltage?

Yes, there is a limit to the amount of work that can be done with a specific voltage. This limit is determined by the amount of charge that can flow through the circuit. Once all of the available charge has been used to do work, the voltage will no longer have an effect on the amount of work done.

Similar threads

  • Introductory Physics Homework Help
Replies
4
Views
669
  • Introductory Physics Homework Help
Replies
12
Views
731
  • Introductory Physics Homework Help
Replies
2
Views
451
  • Introductory Physics Homework Help
Replies
22
Views
2K
  • Introductory Physics Homework Help
Replies
9
Views
1K
  • Introductory Physics Homework Help
Replies
5
Views
1K
  • Introductory Physics Homework Help
Replies
8
Views
6K
  • Introductory Physics Homework Help
Replies
6
Views
232
  • Introductory Physics Homework Help
Replies
7
Views
793
  • Introductory Physics Homework Help
Replies
2
Views
215
Back
Top