Read about point charge | 22 Discussions | Page 1

  1. Z

    Electric field direction on a grounded conducting sphere

    I am required to find the direction of the electric field on the surface of a grounded conducting sphere in the proximity of a point charge ##+q##. The distance between the center of the sphere and the point charge is ##d## and using the method of images we find that the charge of the sphere is...
  2. migueldbg

    Potential from point charge at distance ##l## from conducting sphere

    After looking around a bit, I found that, considering the polar axis to be along the direction of the point charge as suggested by the exercise, the following Legendre polynomial expansion is true: $$\begin{equation}\frac{1}{|\mathbf{r} - \mathbf{r'}|} = \sum_{n=0}^\infty...
  3. A

    Finding the New Acceleration Given Point Charges

    Homework Statement A point charge q1=15.00μC is held fixed in space. From a horizontal distance of 8.00 cm , a small sphere with mass 4.00×10−3kg and charge q2=+2.00μC is fired toward the fixed charge with an initial speed of 40.0 m/s . Gravity can be neglected. What is the acceleration of the...
  4. A

    Find the amount of work to move a particle from point A to B

    Homework Statement How much work should be done on a point charge of q=15 nC to bring it from infinity to a distance of 3 cm from a surface of a charged sphere? Diameter of sphere is 15 cm, its surface charge density is 12 microC/cm2 Homework Equations W=deltaU=q*deltaV v=kQ/r...
  5. Albi Mema

    Forces between the dipole and a point charge

    Homework Statement We have an electric dipole with moment P=2*[10][/-5] pointing in x direction. What is the force experieced by dipole at origin when a point charge Q=3*[10][/-4] is located at (0.014 m ,0,0) Homework Equations 1. [E][/dipole]=(1/4π[ε][/0])(2p/r3) 2. p=qs 3. F=qE 4. τ=pEsinϑ...
  6. N

    B Notion of a zero dimensional point particle?

    When we say a fundamental particle is 0 dimensional, is that literal or figurative? Is it physically possible that a particle has it's properties (like charge, mass) spread out in a finite volume, but can be "shrunk" to increasingly small volumes when we measure it?
  7. PhanicKnight

    [College Physics] Electric field and point charge

    Homework Statement Around a point charge there are three points: A, B and C. Determine the electric field vector for those points. Also, determine the force vector for q0 if it was in point B. Q = 10 µC, a = 1 m, b = sqrt(3) m, q0 = 10 pC 2. The attempt at a solution Here is the attempt at a...
  8. S

    Magnetic Field produced by moving charges

    Homework Statement I have two related questions here. 1. A positive point charge is moving directly toward P. The magnetic field that the point charge produces at P is? 2. Two positive point charges move side by side in the same direction with the same velocity. What is the direction of the...
  9. RoboNerd

    Determining relative amounts of work done

    Homework Statement Homework Equations Work = - (integral of) (E dot dl) The Attempt at a Solution Hi, I know that the right answer is D zero, but I fail to understand why. I said that the answer was A as I have different charges, and I thought that depending on how I approach each...
  10. J

    Find the unknown charges q1 and q2

    Homework Statement The geometrical positions of point-like charges and point A situated in the xy-plane in terms of the length parameter a. The vector of electric field E at point A is shown schematically and measured as E = Exi + Eyj (that is, both Ex and Ey are given). If possible, find the...
  11. heartshapedbox

    What is the gravitational force on the 52[kg] mass

    Homework Statement A particle of mass 52[kg] is at 5.0[m]ˆi a particle of mass 13[kg] is at 12[m]j, and a particle of mass 13[kg] is at −12[m]jˆ. What is the gravitational force on the 52[kg] mass due to the mass at 12[m]jˆ? answer: −1.0 × 10−10[N]ˆı + 2.5 × 10−10[N]jˆ Homework Equations...
  12. H

    Isolated Point Charge and Work?

    This is a really abstract question, and I'm absolutely clueless on how to approach it. I know W= F*d, where F=force and d=distance, as well as W= PEa-PEb. The question reads: The diagram shows an isolated point charge. Marked are four paths (A, B, C, and D) from a point (P1) to point (P2). The...
  13. kostoglotov

    What does it mean to say a battery is however many volts?

    For instance, at a point 1 meter from a 1 nC charge the voltage (potential difference) from the formula V = Kq/r, is given as 9 volts, 9 J/C. So what does it then mean to call a battery 9V, 9 J/C? Is this a battery capable of taking a 1 C charge from infinity and pushing to within 1m of a 1 nC...
  14. L

    Finding the electric field at point P between two charges

    Homework Statement Find the electric field (both magnitude and direction) at point P located between the charges q1 = -3C and q2 = +4C. Point P is 1/3 of the charges' separation distance from q1 and 2/3 of the charges' separation distance from q2. Homework Equations E = kq/d^2 Etotal = E1 + E2...
  15. Mnemonic

    Calculating Electric Field due to two point charges.

    Homework Statement Two points charges. q1=2.4e-6 C is located at (0,0) q2=-5.7e-6 C is located at (3,0) I must calculate the magnitude of the Electric field at (0,0) Homework Equations E=kq/r^2 ; k=9e9 The Attempt at a Solution The electric field at (0,0) due to q2=9e9x(-5.7e-6)/3^2 =...
  16. A

    Electric Fields: Oscillating point charge

    Homework Statement Reading a journal from that crazy old retired physics professor on the hill, you stumble upon a scheme to generate high frequency (HF) radio waves (λ = 10 m). It requires generating an electric field that diverges from a point and increases in strength linearly with respect...
  17. J

    Electric Fields and Charges Fill in the blanks

    Homework Statement [/B] Select the answers which complete the statements below (e.g., if answer A completes the first statement, and answer B the others, enter ABBBB). A) positive B) negative C) neutral D) cannot tell A positive point charge is brought near the outside surface of a...
  18. END

    Point Charge Given Field Maps

    Homework Statement The electric field map is shown below. (Take it to be a self-consistent scale drawing at a particular moment in time.) where \mathrm{q}_4 = +10 C, \mathrm{q}_6 = +10 C What is the charge of \mathrm{q}_5 ? Homework Equations The Attempt at a Solution I've tried the...
  19. END

    Electric Field of Point Charges in Equilateral Triangle

    Homework Statement A point charge q =+6.4 \mu \mathrm{C} is placed at each corner of an equilateral triangle with sides 0.29 \mathrm{m} in length. What is the magnitude of the electric field at the midpoint of any of the three sides of the triangle? Hint: if you are careful to examine the...
  20. G

    Electric potential of a cube of 8 point charges

    Homework Statement Find the Electrostatic potential energy of a cubical configuration of point charges. (One charge on each corner of a cube). Each of the charges is 3.00e and the edge of the cube is 3 cm. Homework Equations U = kqQ/r The Attempt at a Solution I'm pretty sure I understand...
  21. P

    Find the potential difference in a rectangle

    Homework Statement [/B] Figure 20-3, referred to below, is 0.800m wide and 0.400m tall with "A" in the top left corner, "+4 microC" charge in the top right corner, "+2 microC" charge in the bottom left corner, and "B" in the bottom right corner. Two point charges of magnitude +4.00 μC and...
  22. deedsy

    Electric Flux through a sphere from a point charge

    Homework Statement I need to create an equation that can tell me the electric flux through the surface of a sphere (centered at the origin) due to a point charge placed at various locations in/around the sphere. For example, find the electric flux through the sphere (of radius = 1) with a point...
Top