What is Potential difference: Definition and 699 Discussions

Voltage, electric potential difference, electromotive force (emf), electric pressure or electric tension is the difference in electric potential between two points, which (in a static electric field) is defined as the work needed per unit of charge to move a test charge between the two points. In the International System of Units, the derived unit for voltage (potential difference) is named volt. In SI units, work per unit charge is expressed as joules per coulomb, where 1 volt = 1 joule (of work) per 1 coulomb (of charge). The old SI definition for volt used power and current; starting in 1990, the quantum Hall and Josephson effect were used, and recently (2019) fundamental physical constants have been introduced for the definition of all SI units and derived units. Voltage or electric potential difference is denoted symbolically by ∆V, simplified V, or U, for instance in the context of Ohm's or Kirchhoff's circuit laws.
Electric potential differences between points can be caused physically by electric charge build up or imbalance (eg. well known "static" and electronic capacitor) also by electric current through a magnetic field, and by time-varying magnetic fields (eg. dynamo or generator), or some combination of these three. Additionally on a macroscopic scale potential difference can be caused by electrochemical processes (cells and batteries) and pressure induced piezoelectric effect and heat induced emf across metal junctions. These latter processes at microscopic level have the physical origins previously mentioned. A voltmeter can be used to measure the voltage (or potential difference) between two points in a system; often a common reference potential such as the ground of the system is used as one of the points. A voltage may represent either a source of energy (electromotive force) or lost, used, or stored energy (potential drop).

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  1. Muhammad Usman

    How can a magnetic field generate a Potential Difference?

    Problem Statement: Potential difference is the difference in the quantity of charge in both potentials. How does the magnetic field creates this difference of charges ? Relevant Equations: None Hi, I was reading electricity and found that the difference in potential of both end is the...
  2. M

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  3. K

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  4. cianfa72

    Electric potential difference between a battery's + terminal and the ground

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  5. P

    Finding the change in velocity through a potential difference

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  6. fight_club_alum

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  7. fight_club_alum

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  8. fight_club_alum

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  9. Zack K

    Potential difference in a 2 disk system (Capacitor)

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  10. Zack K

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  11. J

    The potential difference of a proton

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  12. C

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  13. K

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  14. physics girl phd

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  15. cookiemnstr510510

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  16. cookiemnstr510510

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  17. cookiemnstr510510

    Understand Electric Potential Energy, Difference & Potential

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  18. Nikhil Rajagopalan

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  19. Pratik Saha

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  20. Krushnaraj Pandya

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  21. R

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  22. Krushnaraj Pandya

    Potential difference in uniform electric field

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  23. M

    A copper wire and an iron wire - Potential difference

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  24. N

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  25. A

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  26. axer

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  27. J

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  29. P

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  30. F

    The value of potential difference between two points

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  31. W

    Understanding Electric Potential and Field in a Ring of Charge

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  32. F

    Find the potential difference between A and B

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  33. T

    Potential Difference Problem - setting up the integral

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  34. J

    Potential difference between two points in a loop

    Homework Statement Homework EquationsThe Attempt at a Solution If we consider the bigger semicircular arc BD alone then potential difference between B and D will be 4BvR . If we consider smaller semicircular arc AC alone then potential difference between A and C will be 2BvR . If we...
  35. Const@ntine

    Potential Difference/Voltage-Graph Help Needed (Long)

    Homework Statement Alright, this is a Lab Exercise, so it's light on an actual introduction and data, but I'll do my best to put into words the whole thing. The gist of it is that we have a Vat with water, a millimetre paper at the bottom, and we put two Equipotential surfaces inside. We charge...
  36. Tomi Kolawole

    The potential difference between a sphere shell and a point

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  37. radiant_june

    Parallel plate electric fields -- # of electrons transferred

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  38. TheBigDig

    Time-dependent potential difference between two ends of a loop

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  39. Physics345

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  40. T

    Charged capacitors connected together, find the final potential difference

    Homework Statement Homework Equations C = Q/V The Attempt at a Solution Q1 = Q2 C1*V1 = C2*V2 2*V1 = 5*V2 V2 = 2/5*V1 V1+V2 =100 7/5*V1 = 100 V1 = 71.4 V Can someone verify my working? Thanks!
  41. T

    Confirming my logic on potential difference

    Homework Statement You’ve decided to protect your house by placing a 5.0 m tall iron lightning rod next to the house. The top is sharpened to a point and the bottom is in good contact with the ground. From your research, you’ve learned that lightning bolts can carry up to 50 kA of current and...
  42. J

    Potential difference and charge across a capacitor

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  43. A

    Why is there confusion about capacitors and potential difference between plates?

    So I understand that a capacitor consists of 2 plates separated by a distance which creates a potential difference between the plates. But I was confused, when watching this physics video it seemed to be saying that once the capacitor was fully charged, the plate closest to the positive terminal...
  44. A

    What is the relationship between voltage and charge in a battery?

    I'm trying to understand what exactly it means in terms of the voltage of a battery. I know that the voltage in a battery is just the potential difference between the two terminals. But, is the negative terminal used as a relative point and seen as 0? If that's the case does 12V mean that the...
  45. IonizingJai

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  46. F

    What potential difference actually means

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  47. Kaneki123

    A Question about potential difference in Wire

    Okay...I got a question. Charges move in a wire due to an electric field across its ends. Now, positive test charge in an electric field would have higher electric potential nearer to the positive plate than anywhere else. Now in case of a circuit, like the one I have drawn, the electric...
  48. S

    Potential difference in between positive and negative charge

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  49. K

    Diagram about potential difference over current

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  50. A

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