Potential difference Definition and 701 Threads

  1. M

    Capacitance potential difference Problem

    [b]1. A 2.05 µF capacitor (#1) is charged to 901 V and a 6.68 µF capacitor (#2) is charged to 671 V. These capacitors are then disconnected from their batteries. Next the positive plates are connected to each other and the negative plates are connected to each other. What will be the potential...
  2. S

    Potential difference between two plates Please help

    A small sphere with mass 2.10 g hangs by a thread between two large parallel vertical plates 5.00 cm apart . The plates are insulating and have uniform surface charge densities + sigma and - sigma . The charge on the sphere is q = 7.70×10−6 C What potential difference between the plates will...
  3. V

    Gravitational Potential Difference in Uniform Gravity Field

    Moderation Note: Split from the original thread, which can be found https://www.physicsforums.com/showthread.php?p=680746#post680746" A uniform field does not have potential difference:smile:
  4. E

    What Potential Difference Is Needed to Stop an Electron?

    Homework Statement What potential difference is needed to stop an electron having an initial speed of 4.2*10^5 m/s? Homework Equations W = delta K W = q*delta V The Attempt at a Solution So I'm pretty sure that the potential difference should be negative in order to stop the...
  5. N

    Calculating Final Speed: Electrons & Potential Difference

    Homework Statement Electrons are accelerated from rest through a potential difference of 250000 V. What is the final speed predicted classically? What is the final speed predicted relativistically? Homework Equations KE=0.5mv^2 KE=mc^2-m0c^2 The Attempt at a Solution...
  6. P

    Relative Acceleration Across a Potential Difference

    Electrons are accelerated from rest through a potential difference of 277000 . a) What is the final speed predicted classically? in m/s b) What is the final speed predicted relativistically? in m/s
  7. X

    The electric potential difference created by point charges.

    Homework Statement A charge of -3.00 C is fixed in place. From a horizontal distance of 0.0450 m, a particle of mass 7.20x10^-3 kg and charge -8.00 C is fired with an initial speed of 65.0 m/s directly toward the fixed charge. How far does the particle travel before its speed is zero...
  8. B

    Potential Difference between two points

    Homework Statement A bird stands on a DC electric transmission line carrying 2800A. The line has 2.5 x 10^-5 ohms resistance per meter, and the bird's feet are 4.0 cm apart. What is the potential difference between the bird's feet?Homework Equations I wish I knew The Attempt at a Solution...
  9. J

    Potential difference between two points located at distances

    Homework Statement Find the potential difference between two points located at distances R_1, and R_2 from a point source. Solution Potential difference = V_{p_1, p_2} = V_{abs_1} - V_{abs_2}. Question Hows is the solution above true? What if the angle formed between P_1, Q, P_2 increases...
  10. U

    Still confused about electric potential difference *read first*

    I understand what voltage is in the context of electrostatics, but the definition of circuits seems foggy to me. The common definition I see is something like "voltage is the amount of work per unit charge to be done on a charge moving from A to B". However, this is usually in the context of...
  11. P

    Potential difference and electric fields

    Homework Statement An electric field is given by E_x = (5 kN/C) x^3. Find the potential difference between the points on the x-axis at x= 1 m and x = 5 m. Answer in units of kV.Homework Equations V = -EdThe Attempt at a Solution V1 = -5*10^6 N/C * 1 = -5*10^6 volts V2 = -5*10^6 * 5 = -25*10^6...
  12. M

    Find the potential difference between a and b

    Homework Statement A network below consists of with three bat- teries, each having an internal resistance, and five resistors. http://images.upload2world.com/get-6-2009-upload2world_com_vypln.jpg Find the magnitude of the potential differ- ence between points a and b. Answer in units...
  13. F

    Electrical Potential Difference between parallel plates

    Alright before I ask the question I'm going to be pretty blunt, I'm not very good at physics at all. I have a great interest and desire to learn physics but it just isn't very easy for me so explanations are going to have to be pretty detailed and even then I still might not get them...
  14. I

    Electric Field Intensity and Potential Difference

    Homework Statement A man walks into an electric field with a small charged object that has a charged value of 4.2 E-6C. At a distance of 10m from the object that is responsible for the electric field, he notices a force of 8.0 N on the object he is carrying. What is the electric field...
  15. M

    Finding potential difference between terminals

    Dear all, can some one help me to solve this question 6 resisitors of resistance 5 ohm are connected to 2 v cell of negligible internal resistance, what will be the pottential difference between terminals, how to slove this thanks
  16. P

    Electric energy - potential difference problem

    Homework Statement On planet Tehar, the free-fall acceleration is the same as that on Earth, but there is also a strong downward electric field that is uniform close to the planet's surface. A 2.00 kg ball having a charge of 5.00 µC is thrown upward at a speed of 20.1 m/s. It hits the ground...
  17. S

    Varied Electrical Potential Difference with Dielectric.

    Hello All, I am wondering why the presence of a dielectric reduces the potential difference of a capacitor (after having been separated from its energy supply). I understand how it works, based around maintaining the same charge, I just don't see why. Thank you for the Help.
  18. N

    HW help: Potential difference between axles?

    Homework Statement An automobile has a speed of 30m/s on a road where the vertical component of the Earth's magnetic field is .00008 webers/square meter. What is the potential difference between the ends of its axles, which are 2 meters long? Homework Equations The Attempt at a...
  19. J

    Electric Fields and Potential Difference

    Just a few brief questions that my teacher did not answer during the last class: 1) Why is the potential difference at any point inside a charged conducting sphere the same? 2) If a charge were placed outside of a charged say, conducting cube, would the electic field drop off...
  20. G

    How Many Electrons Are Transferred in a 450V Capacitor?

    Homework Statement A capacitor has a capacitance of 2.5x10-8F. In charging process, electrons are removed from one plate and placed on the other plate. When the potential difference between the plates is 450v, hoow many electrons have been transferred? Homework Equations C=qV The...
  21. M

    Find the speed of an electron accelerated through a potential difference

    Homework Statement In a color television tube, electrons are accelerated through a potential difference of 20 000 volts. With what speed do the electrons strike the screen? mass of electron=9.109*10^-31kg or 0.51099 MeV/c^2 Homework Equations I don't know which formula I have to use...
  22. D

    Potential difference 'inside' a capacitor

    Suppose we're measuring the P.D of a parallel plate air capacitor from the inside (i.e from the side the 2 plates face each other), will it be different to when we measure it the normal way (like when discharging it)? I think it will be more when measuring it from the inside...many times...
  23. S

    Potential difference in parallel - capacitors

    potential difference in parallel -- capacitors Two capacitors C1 = 3 µF and C2 = 9 µF are connected in parallel across a 11 V battery. They are carefully disconnected so that they are not discharged and are reconnected to each other with positive plate to negative plate and negative plate to...
  24. J

    Potential Difference Across Resistors in Circuit

    Almost forgot to mention: This is a DC Circuit! In the diagram above, find the potential difference across the 3-ohm resistor. a) 1.3 V b) 3.0 V c) 4.0 V d) 5.0 V e) 6.0 V Relevant equations: So far, I used: I = V/R to find current from the battery. Then there's E = IR. (Sorry, LaTeX doesn't...
  25. D

    Potential difference to find the magnitude of the electric field strength

    what are the components to find the magnitude of the electric field strength when only potential difference and that there are two oppositely charged plates that are separated by a given distance.
  26. R

    Find the current through and the potential difference of resistor

    Homework Statement For the circuit shown in the figure, find the current through and the potential difference across each resistor. (Figure attached) a) Find the current through 4.0 ohm resistor. b) Find the potential difference across 4.0 Ohm resistor. Homework Equations V = IR...
  27. R

    Potential difference in capacitor help

    Homework Statement Initially, the switch in the figure is in position A and capacitors C_2 and C_3 are uncharged. Then the switch is flipped to position B. (Figure attached) a) Afterward, what is the charge on C_1 capacitor? b) Afterward, what is the potential difference across C_1...
  28. S

    Finding the potential difference across two wires

    Hello everyone, as you can tell I'm new and just wondering if I could get some help with this question as I'm not sure where exactly I've gone wrong: Homework Statement Two wires are used to connect a lamp to a power supply of negligible internal resistance. The potential difference...
  29. S

    How Long for Potential Difference to Reach 50 Volts in an Oscilloscope?

    Homework Statement The deflection plates in an oscilloscope are 10 cm by 2 cm with a gap distance of 1 mm. A 100 volt potential difference is suddenly applied to the initially uncharged plates through a 900 ohm resistor in series with the deflection plates. How long does it take for the...
  30. C

    Electrical Potential Difference between two plates

    Homework Statement HELP! A charged particle is stationary between two horizontal charged plates. The plates are 2.0 cm apart. The particle has a mass of 4.0X10^-13 kg and a charge of 2.4 X 10^-18 C. Find the potential difference between the plates. Homework Equations V= EPE/q ...
  31. I

    Ultracapacitors - How long until the potential difference drops to 6V

    Homework Statement Compact "ultracapacitors" are with capacitance values up to several thousand farads are now commercially available. One application for ultracapacitors is in providing power for electrical circuits when other sources (such as a battery) are turned off. Assume a 1200-F...
  32. D

    Potential difference between the plates?

    Homework Statement A small electrically charged object is suspended by a thread between the vertical plates of a parallel-plate capacitor. The acceleration of gravity is 9.8 m/s^2. What is the potential difference between the plates? Answer in units of kV. Given: tetha = 14 degrees...
  33. C

    RLC circuit potential difference

    Homework Statement An L-R-C series circuit is constructed using a 175{ \Omega} resistor, a 12.5 muF capacitor, and an 8.00-mH inductor, all connected across an ac source having a variable frequency and a voltage amplitude of 25.0 V. At the angular frequency in part A, find the potential...
  34. W

    Potential Difference in and Electron/de Broglie Equation

    Homework Statement Through what potential difference should you accelerate an electron from rest, such that it's de Broglie wavelength will be 0.1 nm. Homework Equations E = hf λf = c The Attempt at a Solution My Thinking was; E = hf E = hλ/c E= 6.626e-34 * 1e-10/3e8...
  35. J

    Finding potential difference to accelerate the ion

    Homework Statement What potential difference is needed to accelerate a He + ion (charge +e, mass 4 u) from rest to a speed of 2.0 * 10^6 m/s?Homework Equations Kf + Uf = Ki + Ui U = qV where V is potential difference (volts) K = (1/2)mv^2 The Attempt at a Solution I chose the rest point to...
  36. H

    Potential Difference b/w Sphere & Cond. Shell | Electrostats

    From Electrostatics: A solid conducting sphere of charge Q is surrounded by an uncharged concentric conducting spherical shell. The potential difference between the sphere and the shell is V. If the shell is now given a charge of -3 Q , what is the new potential difference between them?
  37. K

    Calculating Potential Difference in a Uniform Electric Field | Example Problem

    I am wondering if I did this right. Homework Statement What is the potential difference between the points (x_i, y_i) = (0cm, -5cm) and (x_f, y_f) = (1cm, 4cm) in a uniform electric field equal to E = (20000i - 50000j) V/m ? Homework Equations \Delta V = V(s_{f})-V(s_{i}) =...
  38. X

    Calculating Potential Difference for Capacitor Heating of Water

    Homework Statement A 4.63mF capacitor has stored energy to heat 3.00kf of water from 22 degrees C to 94.5 degrees C. What the potential difference? Homework Equations Q= mC delta T W= Q sq/2C V=W/C The Attempt at a Solution Q= mC delta T Q= 3kg* 4.184* ( 94.5-22) = 910.02 J...
  39. C

    Potential difference to stop an electron question

    Homework Statement An electron with an initial speed of 4.70×105m/s is brought to rest by an electric field. What was the potential difference that stopped the electron? Unknown: potential difference or \DeltaV Known: vo=initial speed m=mass of electron q=charge of electron...
  40. S

    Battery provides a potential difference problem

    Homework Statement The capacitor in Fig. 25-25 has a capacitance of 27 µF and is initially uncharged. The battery provides a potential difference of 118 V. After switch S is closed, how much charge will pass through it? (picture is in the attachment) Homework Equations C = Q/V U =...
  41. P

    Potential difference of falling charge particle

    Homework Statement A particle of mass 7*10e-5 kg and charge 1e-6 C from point A to point B a distance of 3 m in the Earth's gravitational field. The kinetic energy of the particle decreases by 5.3mJ during this movement. The acceleration of gravity is 9.8 m/s^2. What is the potential...
  42. W

    Potential difference across each capacitor

    Homework Statement How many 1 microF capacitors connected in parallel would it take to store a total charge of 1 mC if the potential difference across each capacitor is 10.0V? Homework Equations C=Q/V in parallel --> Ceq=C1+C2+C3... The Attempt at a Solution...
  43. J

    Electricity question potential difference

    Homework Statement Givens: ΔV1 = 14 V, ΔV2 = 4.6 V, ΔV3 = 8.8 V, R = 3.0 ) Homework Equations The Attempt at a Solution I thought what I was doing was close lol... apparently not. I decided to Combine 10 ohm and 3 ohm into 13 ohms in series with 14V and Combine 5 and 2 ohms into 7...
  44. L

    Potential Difference Near a Charged Rod

    Homework Statement A long rod of length L = 7.8 m carries a uniform charge Q = -6.5e-08 coulombs. Calculate the potential difference VC - VA. The distance c is 4 cm, the distance b is 11 cm, and the distance a is 4 cm. Only part of the rod is shown in the diagram (it is longer than shown)...
  45. T

    Electric Potential Difference Question (Parallel plates, higher potential)

    Homework Statement I have two large parallel plates that are conducting and separated by 10.0cm. The charges on the plates are uniform and equal in magnitude but opposite in sign. The difference in potential between the two is 500 V. The first question concerning this is which plate...
  46. P

    Answer: Potential Difference Va-Vb for 4.3 nC Particle in 225 N/C Field

    Homework Statement a uniform electric field has magnitude E = 225 N/C and is directed to the right. A particle with charge +4.3 nC moves along the straight line from a to b. What is the potential difference Va - Vb between points a and b? Homework Equations Potential dif=Va-Vb The...
  47. D

    Line Integral + Potential Difference Problem Need

    Homework Statement The cyclotron is a device for accelerating charged particles. It requires changing electric fields and a magnetic field, but it can be modeled using (non-physical) static electric fields and potentials as we will do in this problem. Keep in mind that these fields cannot...
  48. I

    Momentum and kinetic energy through potential difference

    An electron and a proton are each accelerated through a potential difference of 10 million volts. find the momentum (in MeV/c) and the kinetic energy (in MeV) of each. ---------------------------- I started by finding the masses of the proton and electron in MeV/c^2, but i don't know where...
  49. B

    What is potential difference uniform electric field

    Homework Statement What is the potential difference (in V) between xi = 18.5 cm and xf = 82.2 cm in the uniform electric field Ex = 4920 V/m? Homework Equations Not sure? The Attempt at a Solution Its simple but I am having problems figuring it out. I have a feeling it has to do...
  50. N

    Charge Density of wire with potential difference

    Problem: Consider a long charged straight wire that lies fixed and a particle of charge +2e and mass 6.70E-27 kg. When the particle is at a distance 1.91 cm from the wire it has a speed 2.80E+5 m/s, going away from the wire. When it is at a new distance of 4.01 cm, its speed is 3.20E+6 m/s...
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