Potential difference Definition and 701 Threads

  1. R

    Potential Difference b/t 2 points

    Ok, I've got a problem: The electric field in a region of space has the components Ey = Ez = 0 and Ex = (3.91 N/C)x. Point A is on the y-axis at y = 2.83 m, and point B is on the x-axis at x = 3.97 m. What is the potential difference VB - VA? I have tried integrating E (wrt x) * x from...
  2. B

    Electric potential and potential difference

    hiya 1) Some quotes from physics tutorial site: The above all makes sense. But this is where I get lost: Wouldn't it be more correct if instead we said: *The kinetic energy charge has was transformed from charge's potential energy, and this kinetic energy gets lost as charge goes...
  3. J

    Calculating Minimum Distance Between Two Power Lines (50 kV)

    If you know the potential difference between two power lines, (50 kV) and that the electric field between them is uniform, how would you go about working out the minimum distance they can be separated without discharge occurring between lines? I've looked at the equations for Coulomb's law...
  4. S

    Conservation of Energy applied to a potential difference.

    I am looking for some help on how to apply the law of energy conservation when applied to a voltage difference. Specifically, here is what I am thinking. If you build a voltage difference on a capacitor, I know it takes energy to build that difference, but once it is there, can the...
  5. R

    Velocity of an ion given the potential difference it is accelerated through?

    I'm trying to find the mass of an unknown ion and I think the equation I'm down to to find the mass only requires me to determine the velocity before I can calculate mass -- but I don't know how. Could anyone help me out and direct me to an equation(s) that would help me find the velocity of...
  6. J

    Determining Currents and Potential Difference in a Circuit

    I'm having trouble with curcuits, my first problem is that I'm not sure if this is a combination parallel-series curcuit? For the simple circuit (attached diagram) determine the current through each resistor and the potential difference at the 5 ohm resistor. I think that the 2 ohm...
  7. J

    Electric work and potential difference

    I need a little help with this question: Calculate the work needed to move a 1.5uC test charge from point B to point D. (I have attached the diagram) The first part of the question required me to find the electric field at the points A, B, C and D. Which I think I figured out ok. I...
  8. J

    Formula for electron accelerated across potential difference?

    I got this homework and I don't know what formula to use on these problems: An electron is accelerated across a potential difference of 54V. (a) Find the maximum velocity of the electron. (b) Calculate the deBroglie wavelength of the electron. Please help!
  9. T

    What guarantee Kirchoff's law of potential difference?

    Kirchoff's law states that, the potential difference along a closed circuit must be ZERO. Now, let's do a simple question 1. We have a simple circuit consists of INDUCTOR and Voltage source-->V=V.sin(wt) At any instant, why must the voltage supplied equal the voltage generated in the...
  10. M

    How Is Potential Difference Calculated in a Parallel-Plate Capacitor?

    Here is the question: A parallel-plate capacitor is made of two circular plates, each with a diameter of .0025m. The plates of this capacitor are separated by a space of .00014m. What is the potential difference between a point midway between the plates and a point that is .00011m from one of...
  11. S

    Electric Potential Difference homework

    Point A is at a potential of +220 V, and point B is at a potential of -120 V. An alpha-particle is a helium nucleus that contains two protons and two neutrons; the neutrons are electrically neutral. An alpha-particle starts from rest at A and accelerates toward B. When the alpha-particle arrives...
  12. O

    What Potential Difference Between Plates Causes a 30° Thread Angle?

    Can anyone help me with a hint of some sort? I am lost... A small sphere with mass 1.50 g hangs by a thread between two parallel vertical plates 5.00 cm apart. The plates are insulating and have uniform surface charge densities + and -. The charge on the sphere is q = 8.90 10-6 C. What...
  13. D

    Potential difference and Kinetic energy

    A 4.0g object carries a charge of 20uC. The object is accelerated from rest through a potential difference, and afterward the ball is moving at 2.0 m/s. What is the magnitude of the potential difference? I know i have to use the law of conservation Potential_initial + KE_initial =...
  14. H

    What is the potential difference VA-VB?

    Points A (3 m, 2 m) and B (6 m, 6 m) are in a region where the electric field is uniform and given by E = Exi + Eyj, where Ex = 3 N/C and Ey = 2 N/C. What is the potential difference VA-VB? Answer in units of V. I used E(rB-rA) sqr rt(13) times (sqr rt (72) - sqr rt (13)) = 17.59...
  15. B

    Electric Potential Difference Created by Point Charges

    I'm working on the following problem: The drawing shows four point charges. The value of q is 2.0 µC, and the distance d is 0.74 m. Find the total potential at the location P. Assume that the potential of a point charge is zero at infinity...
  16. S

    Simple Potential Difference Question

    Can someone help me to describe the differences between a 12V car battery and a 9V radio battery. They both convert chemical energy into electrical energy, but the car battery has the capacity for much higher currents with similar voltage to the 9V. Thanks
  17. K

    Potential difference between two plates

    The problem says that there are two parallel plates having charges of equal magnitude but opposite signs and they are separated by 16cm. Each plate has a surface charge of 31 nc/m2(sorry don't know how to superscript). I need to find the potential difference between the plates. I thought I...
  18. A

    Potential Difference at Center of Square with q = 0.1uC

    Magnitude and direction of E Ok, hear is the question I need to answer, "What is "E" in direction and magnitude at the centre of a square if q=0.1uC." Now my question is about the diagram that is provided I don't know what the values at each of the corners of the square are for, they are simply...
  19. S

    Ignition: Potential Difference & Electric Field for Spark Plug

    Question: Spark plug in car has electrodes. They are spearated by 0.6mm. To create spark electric field of 3.0x10^6 V/m is needed. a) What Potential difference is requuired to initiate the ignition. Possible Answer: Is this just multiply Electric field by the distance between electrodes...
  20. P

    Quantum - potential difference problem.

    question: A certain proton needs to have a lamba of 0.0055 x 10^-9m. What potential difference must this proton be accelerated to achieve this wavelength? what i know: im assuming that what we need to find in this question is the amount of kinetic enegry needed to achieve such a lambda...
  21. M

    What is the rms potential difference across the resistor?

    Hello every9one I'm stuck on finding the first part: A series RLC circuit is driven by an alternating source at a frequency of 380 Hz and an emf amplitude of 90.0 V. The resistance is 20.0 , the capacitance is 12.1 µF, and the inductance is 24.2 mH. What is the rms potential difference...
  22. B

    Why Are There Different Reference Potentials in Electric Potential Formulas?

    There seems to be two different uses of potential difference that either contradict each other, or at the very least make it very confusing. Let me write the three different forms: Definition: Vf-Vi= -E*d Differential: dV=-E*dr (Vi=0) Point Charge: V=E*r (Vf=0) What is with the different...
  23. M

    Finding potential difference of Va-Vb, circuits.

    Hello everyone, I'm confused, i know the loop rule and the sum of the Potential differences is 0 in a closed circuit but I need to find the Va-Vb of the circuit. Here is the picture: http://www.webassign.net/hrw/hrw7_27-40.gif and here is the info: the resistances are R1 = 1 , R2 = 2.2 , and...
  24. L

    Geiger Counter and Potential Difference

    In this problem I am getting stuck on how to find the potential difference. I don't know where to begin. In a Geiger Counter suppose the radius of the central wire is 145 micrometers and the radius of a hollow cylinder is 1.80 cm. What potential difference between the wire and the cylinder...
  25. L

    Electromag Potential difference

    Hello forum dwellers :D I recent have been coming across questions which deal with large arrangements of resistors and in other cases circuits with open switches where the goal is to calculate the potential difference. These questions have been causing me quite a bit of strife and i was...
  26. T

    Potential Difference: Effects of Voltmeter Connection

    what happens to the potential difference of a source of emf when a voltmeter is connected across its terminals? tanx. :smile:
  27. D

    What equation am I supposed to use for potential difference?

    A huge 4.0-F capacitor has enough stored energy to heat 2.5 kg of water from 21 degree Celsius to 95 degree Celsius. What is the potential difference across the plates? What equation am I supposed to use for potential difference? Is it V = Change in PE / q V= - W / q...
  28. F

    Potential Difference in Series & Parallel Circuits

    If you have two globes in series and one globe in parallel all connected to a circuit, how can you determine the potential difference?
  29. H

    Calculating Electron Speed in a TV Screen Using 2.0 kV Potential Difference

    Electrons in a television set are accelerated through a potential difference of 2.0 kV. (a) Find the speed of the electrons when they reach the screen. Ignore any relativistic effects. how to do this i have no idea what formula to use
  30. J

    Calculating the Electric Potential Difference of a Helium Balloon

    I'm learning about charge right now and I have no idea how to start this one.. any help is appreciated. A helium balloon has a charge of q = 5.5 x 10^-8. It rises vertically into the air. d = 600m. from the surface of the Earth to final position A. The electric field that normally exists in...
  31. N

    Uniformly Charged Cone - Potential Difference

    We have a right circular cone of base radius a and height a with a uniform surface charge sigma. I want to determine the potential difference between the apex of the cone and the center of the base (this cone doesn't have any charge on the base). My plan of attack for the problem was to...
  32. C

    Electric Potential Difference and charges

    Here's the problem I am having trouble with, even though i think it should be simple... Four identical charges (+3.5uC each) are brought from infinity and fixed to a straight line. The charges are located .35m apart. Determine the electric potential energy of the group. So I've tried...
  33. T

    Battery and potential difference

    A battery fully charges a parallel plate air gap capacitor. The battery is removed and the plates are pulled apart. What happens to the potential difference between the plates as they are being separated? So I guess resistance and I operate over a certain length. So the length is...
  34. J

    What Is the Potential Difference Between Two Charged Parallel Plates?

    Two parallel plates having charges of equal magnitude but opposite sign are separated by .12 m. Each plate has a surface charge density of 36 nC/m^2. Determine the potential difference between the plates. I have to admit I am at a bit of a loss on how to answer this (lettings S...
  35. T

    Potential difference between plates in a B-Field?

    How is potential difference found between two plates in a B-field? Any help is greatly appreciated.
  36. K

    Calculating Plate Spacing for 162 V Parallel-Plate Capacitor

    When a potential difference of 162 V is applied to the plates of a parallel-plate capacitor, the plates carry a surface charge density of 33.0 nC/cm^2. What is the spacing between the plates? >> I'm rather confused with this question. I know that deltaV = Ed and I tried solving for d, but I...
  37. K

    Electronics - Potential Difference & Electrical Potential

    1. Through what potential difference would an electron need to be accelerated for it to achieve a speed of 50.0% of the speed of light, starting from rest? The speed of light is c = 3.00 108 m/s. >> I'm really not too sure what to do with this problem. I took .50*3.00e8 and got 1.50e8...
  38. B

    Why Does a Series Circuit Show Zero Potential Difference Despite Components?

    I've been thinking while studying physics and came up with the following problem: A current I, starting at a point A, flows through a resistor with R=25 kΩ, a capacitor with C=4milliF, and an inductor with L=7 Henry to finish in point B. At a time when Q=8 milliC and the current I=0.2...
  39. 7

    What's the Difference Between Voltage and Electrical Potential Energy?

    1. potential difference = voltage? 2. What's the difference between electrical energy and electrical potential energy ? 3. In light bulbs, when the resistance is increased, is it brighter? 4. When voltmeter or ammeter is equipped with the electric circuit, will the light bulb in the circuit...
  40. G

    Electron accelerated by potential difference

    An electron is accelerated by a potential difference of, say, 100V. How much greater would its final speed be if it were accelerated with four times as much voltage?
  41. I

    Potential difference and static charge

    Hi I am doing a report on electrostatic force. It involves 2 steel plates which are connected to a 5kV DC power supply and are separated 8cm from each other. A table tennis ball painted in metallic paint (to conduct) is hung from a nylon wire between the two plates. When the power supply is...
  42. C

    Potential Difference of Electrons and Balmer Series

    A beam of electrons bombards a sample of hydrogen. Through what potential difference must the electrons have been accelerated if the first line of the Balmer series is to be emitted? How does this even begin?
  43. S

    Please help How to find the potential difference of a spherical shell

    I can frankly say I'm totally confused on how to solve this problem. Here it is: A think spherical shell of charge Q and uniform volume charge density p is bounded by radii r1 and r1 where r2>r1. WIth V=0 at infinity find the electric potential V as a function of the distance from the centre...
  44. Q

    Solving [problem2.26]: A Conical Surface's Potential Difference

    I have a problem from Griffiths Introduction to EM [problem2.26] A conical surface (an empty ice-cream cone) carries a uniform surface charge <sigma>. The height of the cone is h, and the radius of the top is R. Find the potential difference between points a(the vertex) and b (the center of...
  45. W

    Calculating Potential Difference: Work Done and Kinetic Energy Relationship

    Please assist me with this The work done to move a 1.0 C charge from point P to Q is 3.0 * 10^-4J. If the charge starts from rest and has 1.0 * 10^-4J of kinetic energy when it reaches point Q, what must the potential difference be between P and Q? For this would I use Work done =...
  46. N

    Potential difference and ohms law

    A 3Ohm and a 1.5 ohm resistor are wired in paralles and the combination is wired in series to a 4 ohm resistor and a 10 V emf device. The potential difference on across the 3 ohm resistor is? I reduced the 2 in parrallel to 1.875 ohms and then addes the 4 ohm, which gave me a total...
  47. E

    What is the potential difference between the plates?

    Here's my problem: A parallel-plate air capacitor has a capacitance of 730 picoFarads. The charge on each plate is 2.95 microCoulombs. a) What is the potential difference between the plates? I used the equation V=Q/C to get 2.4746E-4 V, but this is incorrect. b)If the charge is kept...
  48. S

    Calculating Electron Energy from Potential Difference

    Currents-- Please Help An electron is accelerated from rest through a potential difference of 1.5Mv. what is the final energy of teh electron.
  49. M

    How to Calculate Potential Difference in Various Charge Configurations?

    Problem 4. Given: k_e=8.98755*10^9 nm^2/C^2 and g=9.8 m/s^2. find the potential differnece between a point infinitely far away and a point 1.4 cm from a proton. Answer in units of V. Note: I don't know where to start! Problem 6. Given: k_e=8.98755*10^9 nm^2/C^2 and g=9.8 m/s^2...
  50. J

    What is the difference between the potential difference, and its emf?

    ok, i guess i didnt see this forum ... i posted in another forum my question: https://www.physicsforums.com/showthread.php?s=&threadid=7593 ok, I am taking engineering physics II ... unfortunately, I am forced to take this as part of my COMPUTER SCIENCE degree ... (why i have no...
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