Electric Definition and 1000 Threads

  1. D

    Magnitude of the Electric Field at the Following Distances

    Homework Statement The figure below shows a spherical shell with uniform volume charge density ρ = 1.87 nC/m3, inner radius a = 15.0 cm, and outer radius b = 2.60a. [Reference Picture] What is the magnitude of the electric field at the following radial distances? Homework Equations...
  2. P

    Emitting one or two opposite charges along the x-axis

    Let's consider that I have an emitter that can emit both negative and positive electric charges. Here let's consider only scenarios with two particles (one negative and one positive) that start initially at the tip of some electrode, where one or both the charges will separate from at the same...
  3. Philosophaie

    I Electric Dipole Moments: Sun, Earth, Planets, Minor Planets, Moons

    Is there a table of Electric Dipole Moments, ##\bar p##, for the Sun, Earth, Planets, Minor Planets and Moons?
  4. G

    Electric field integral: Convergence where ρ is nonzero

    Hi. I know how to use Gauss' Law to find the electric field in- and outside a homogeneously charged sphere. But say I wanted to compute this directly via integration, how would I evaluate the integral...
  5. R

    Electric potential due to collection of charged particles

    Homework Statement A particle with charge q1 = -6.75x10^-6 is located at (0,3.25x10^-2 m ) and a second particle with charge 3.2x10^-6 is located at (0,-2.75x10^-2 m) what is the electric potential due to the two charges at the origin? Homework Equations V = kq/r The Attempt at a Solution So...
  6. N

    Using Gauss' Law to Calculate electric field near rod.

    Homework Statement No variables, just a conceptual question. Homework Equations Flux = EA = Q/ε The Attempt at a Solution Given a uniformly charged rod of FINITE length, could we use Gauss' law for electric flux to calculate the field at a point p a distance x away from the rod, so long as the...
  7. B

    Determine work done by electric field

    Homework Statement Given electric field ##\vec E = 6x^2\hat i +6y\hat j+4\hat z## v/m Find ## V_{MN}## if both M and N separate by M(2,6,-1) and N(-3,-3,2) Homework Equations The Attempt at a Solution here i find ##V_{MN}## by unit vector from N to M is ##\frac 1 {\sqrt (115)}(5\hat i +9\hat...
  8. V

    Battery sizing in an electric vehicle

    Hi.. i am working on a developemnt of electric vehicle as my final year project..i have calculated the max. power required by 800 kg vehicle is 30 kw.. so i am using 30 kw 3 phase AC induction motor.. now can you please help me out in sizing my battery pack.. weight : 800kg max. velocity : 80...
  9. Philosophaie

    Electric Field and Electric Dipole Moment for a Dipole

    The Magnetic Dipole Moment for a Magnetic Field for a dipole oriented on the x-y axis is: ##\bar m = |m| \hat z## The Magnetic Field is: ##\bar B = \frac{\mhu_0}{4 * \pi * |\bar r|^5} * 3 * \bar r * (\bar m . \bar r) - \bar m * |\bar r|^2## Vector Potential is: ##\bar A = \frac{\mhu_0}{4 * \pi...
  10. P

    Electric field above an off-center finite line charge

    Homework Statement There is a finite line charge with length L = 1 meter and linear charge density λ = 1*10^-16 C/m. Point P is h = 70cm above the line charge and distance x from the right end of the line charge. The magnitude and direction of the electric field at point P must be found. The...
  11. RJLiberator

    How Do You Calculate Electric Potential for a Given Charge Distribution?

    Homework Statement The volume charge density for some charge configuration is given as ## \rho (x,y,z) = \lambda \delta(x) \delta(z) [\theta(y+L)-\theta(y-L)]## where ## \theta(x)## is the step function, defined as ##\theta(x)=1## for x>0 and 0 for x<0. a) Calculate V(x,y,z), the potential...
  12. P

    Calculate strength of the electric field at indicated point

    Homework Statement https://imgur.com/a/wpir4 [/B] a. What is the strength of the electric field at the position indicated by the dot in the figure? Use the following values: q1 = 1.09 nC, q2=0.93 nC, d1=2.49 cm, d2=6.9 cm, d3 = 4.27 cm. b. What is the direction of the electric field at the...
  13. G

    What happens to the electric field's phase upon reflection?

    I have a problem with the phase of an electric field as it is reflected by and transmitted through a dielectric interface. At the boundary between the two media, all waves must exist simultaneously and the tangential component must be equal on both sides of the interface, right? Therefore for...
  14. T

    Electric field inside hollow conductor with a charge

    Ok, this might be a really dumb question, but I still am asking it: I was reading about gauss' Law when it comes to a hollow conductor with a (say) point charge inside it, and it seems intuitive to me that, in electrostatic equilibrium, the charges rearrange themselves to cancel the electric...
  15. Spinnor

    I Electric and Color charge in String Theory

    I get a gist of how electric charge comes about in string theory here, https://physics.stackexchange.com/questions/5665/electric-charge-in-string-theory How much needs to be amended to the above answer to understand how color charge comes about in string theory? I assume there are interesting...
  16. F

    Will this man get an electric shock

    If a properly insulated man touches with one hand +ve terminal of a 120 V battery and with another hand -ve terminal of (Edit: an another) 120V battery (two batteries are totally isolated, not connected in any way) then will he get electrical shock ? ( I am guessing , not). But if -ve terminals...
  17. T

    Electric field inside non-conducting spherical shell

    Homework Statement Figure 23-30 shows two nonconducting spherical shells fixed in place. Shell 1 has uniform surface charge density +6.0 µC/m2 on its outer surface and radius 3.0 cm. Shell 2 has uniform surface charge density -3.8 µC/m2 on its outer surface and radius 2.0 cm. The shell centers...
  18. Epoch

    Electricity: electric field in a point Between Two Charges

    Homework Statement I've seen many books writing the cosine rule like this: a^2 = b^2 + c^2 - 2bc cos A My electricity textbook for an electric field in a point between two charges says this: E resultant = root[E1^2 + E2^2 + 2*E1*E2*cos(angle between E1 and E2)] In the first equation it is -2...
  19. M

    Finding electric potential given two point charges

    Homework Statement Find the potential at points P1, P2, P3, and P4 in the diagram due to the two given charges. Homework Equations VP =k∑qi/ri p = q ⋅ d The Attempt at a Solution I'm not sure how to approach the problem. I thought about using that given equation four times and adding it all...
  20. M

    Strength of electric field given potential difference

    Homework Statement What is the strength of the electric field between two parallel conducting plates separated by 1.00 cm and having a potential difference (voltage) between them of 1.50×104 V? Homework Equations ΔV = qΔU ΔV = -∫E⋅dl E = kq/r2 The Attempt at a Solution I am not sure where to...
  21. I

    Electric power and internal resistance

    Homework Statement Today I did a laboratory work in which I had to find power and internal resistance. I used an ordinary battery so it's closed circuit. I did all tasks except writing a hypothesis and conclusion I can't really think of it. I don't know what to write since I just measure using...
  22. T

    Rotating a spherical conductor in an Electric field

    Hi, I recently came across the familiar image of a metal sphere in an electric field: https://i.stack.imgur.com/x58Ia.jpg I noted how the free-charges on the surface of the sphere align with the electric field lines as opposite charges are attracted. Then I wondered, 'what if the sphere was...
  23. Brendan Webb

    Electric Field of Equilateral Triangle

    Homework Statement Consider an equilateral triangle of side 15.6cm. A charge of +2.0μC is placed at one vertex and charges -4μC each are placed at the two. Determine the electric field at the centre of the triangle. Homework Equations E=kQ/r^2 The Attempt at a Solution I am hoping someone...
  24. R

    Electric Flux Equation for Rotating Loop?

    Homework Statement A circular loop with radius r is rotating with constant angular velocity w in a uniform electric field with magnitude E. The axis of rotation is perpendicular to the electric field direction and is along the diameter of the loop.Initially, the electric flux through the loop...
  25. G

    Limiting output voltage of an electric fence energiser

    My home-made energiser runs off a car battery and uses a 555 timer to pulse a Darlington-style pair of transistors. These pulse the primary of an ignition coil. Since an electric fence is an open circuit, I'm concerned about excessive voltages developing in the coil secondary causing...
  26. T

    Engineering Solving Circuit Diagram Homework - Test Prep Tips

    Homework Statement [/B] A screenshot with everything given Homework Equations No idea The Attempt at a Solution No idea I'm not sure how to solve this or where to look for a solution. I was given this yesterday and have a test tomorrow. The professor has not gone over this at anytime...
  27. K

    Making an electric unicycle really self-balanced

    I recently came across electric unicycles, a cool and fun way fpr transportation. The wheel balances as a Segway by applying power to the wheel. (the classis reverse pendula). However, since its a unicycle, it does not balance sideways, and I imagine that this colud be solved with a...
  28. Iftekhar Uddin

    How an Electric Field is affected by an Insulator

    I looked through this forum post for an answer to my problem. It gave me enough insight to try and come to some conclusions but I'm still confused on some parts here and there about how I got my final answer. 1. Homework Statement A uniformly charged, straight filament 7.70 m in length has a...
  29. C

    Electric Field of Line Charge with Displaced Origin

    Homework Statement Positive charge Q is distributed uniformly along the x-axis from x = 0 to x = a. Determine a. The electric field produced by the charge distribution Q at points on the positive x-axis where x > a. b. A point charge q is then placed at x = a + r. Determine force on q due to Q...
  30. R

    Magnitude of electric field at point A using components

    Homework Statement https://imgur.com/gallery/YwCap In side are image of figure, and questions.Homework Equations E = kq/r^2 The Attempt at a Solution So I have an electric field where the y compontents cancel. I have 2Ecos(∂) = E (Electric field at point A) - 2 because there is a top and...
  31. L

    Can E=V/d be used to calculate the electric field of a dipole?

    This is from a lab where my team found the equipotential lines from the electric field of a dipole. The information I was given to calculate the magnitude of the electric field seems too simple, and for some reason I'm expecting this to be more complex. So, this is my attempt at double checking...
  32. A

    Breakdown voltage of humid air in uniform electric field

    Could anyone please let me know if breakthrough spark can happen, or, in general, what will happen in the below system? Note 1: the dielectric layers have a much higher breakthrough voltage than humid air. Note 2: the intensity of the electric field that develops in the flow of the humid air is...
  33. T

    Electric field (in)dependent of distance?

    Hi guys, I was reading about electromagnetism, specifically about the application of Gauss' Law to an infinite charged sheet, and how its electric field doesn't depend on the distance from the sheet. I think I have finally managed to wrap my mind around the concept intuitively, based on one of...
  34. K

    Gradient, Electric Potential, and Electric Field

    Hi guys! I was wondering about the relation between the Gradient, Electric Potential, and Electric Field. I know that if you take the Gradient of a scalar field, you get a resultant vector field in which the vector points in the direction of greatest increase when you take a infinitesimally...
  35. R

    Simple Electric field question -- Charged sphere

    Homework Statement A sphere with a charge of -3.5 x 10^-9 C and a radius of 1.0x10^-2 m is located at the origin of a coordinate system. What is the electric field 1.75 x 10^-2 m away from the center of the sphere along the positive y axis? Homework Equations e = kQ/r^2 The Attempt at a...
  36. D

    Electric Field of a cube with a rod

    Homework Statement The electric field at 2 cm from the center of long copper rod of radius 1 cm has a magnitude ##3 \frac{N}{C}## and directed outward from the axis of the rod. (a) How much charge per unit length exists on the copper rod? (b) What would be the electric flux through a cube of...
  37. T

    Electric field of a ring:integrate over dq or ds?

    Hi people, I was reading on my textbook on electromagnetism (Halliday) about using integral to field the electric field of a charged ring (1D) at a point P located on an axis perpendicular to the ring's plane. The ring is uniformly charged. The book (and my professor) both breakdown each element...
  38. RJLiberator

    EM: Electric field, Two thin rods uniform line charge

    Homework Statement Two identical thin rods of length L carry the same uniform line charge distribution (charge per unit length) of . If the two rods are collinear (aligned along the same line), with a distance of d between their nearest ends, calculate the Coulomb force (magnitude and...
  39. D

    Electric field of a positive plate

    Homework Statement There is a large positively charged plate whose charge density is ##\sigma = 2.0 × 10^{-5}\frac{C}{m^2}##. What is the electric field at a point P, that is not enclosed between the plates. Homework Equations For an infinite sheet: $$\vec E = \frac{\sigma}{2\varepsilon_0}\hat...
  40. K

    Deriving the energy density of the Electric Field

    Homework Statement Taken from Purcell Problem 1.33 Consider the electric field of two protons a distance b apart. The potential energy of the system ought to be given by U=∫E2dv. Let E1 be the field of one particle alone and E2 that of the other. Evaluate ε0∫E1⋅E2dv. Set one of the protons...
  41. D

    Particle traveling towards a plate with an Electric Field

    Homework Statement From a distance of 10 cm, a proton is projected with a speed of ##v = 4.0 × 106 \frac{m}{s}## directly at a large, positively charged plate whose charge density is ##\sigma = 2.0 × 10^{-5} \frac{C}{m^2}##. (See below.) (a) Does the proton reach the plate? (b) If not, how far...
  42. N

    Finding the Charge on an Ion in a Zero Electric Field

    Homework Statement A proton is at the origin and an ion is at x1 = 6 nm If the electric field is zero at x2 = -3 nm , what is the charge on the ion? Homework Equations for ion The Attempt at a Solution https://imgur.com/ryyuQBq I just have used all my attempts besides one. So I...
  43. D

    Electric Field between Two Thin Conducting Plates

    Homework Statement Two thin conducting plates, each 25.0 cm on a side, are situated parallel to one another and 5.0 mm apart. If ##10^{-11}## electrons are moved from one plate to the other, what is the electric field between the plates?Homework Equations $$\vec E(P) = \frac{1}{4\pi...
  44. W

    Calculating electric flux when given a charge (Gauss)

    Homework Statement A charge Q=5.14 nC is located at the center is located at the center of a Gaussian sphere of radius R=10.0 cm . The sphere lies within a uniform upward electric field E=2100 NC The net outward electric flux through the sphere is What? Second problem (bonus round!) A...
  45. Z

    Coulomb's force - magnitude of the electric force

    Homework Statement Show that the magnitude of the electric force on each ball is given by Fe = mgtanθ/ (cosα+ sinαtanθ) where θ = arcsin(x2/L) α = arcsin((y2-y1)/r) r = √((x2-x1)^2+(y2-y1)^2) This is a question from my coulomb's law lab, where 2 styrofoam balls where charged, one was hung on a...
  46. E

    Electric field outside conductor surface

    I'm confused as to how this expression E= (δ/εo) can't be used to calculate the electric field of a perfectly flat part of a surface even farther from just above the surface.If you just extend the same cylindrical Gaussian surface used for this proof, wouldn't the field stay the same no matter...
  47. B

    Electric field in an infinite layer

    Homework Statement In the layer ##0<z<a## there is a uniform and constant density of charge ##\rho>0##. In the layer ##-a<z<0## the density of charge is ##\rho<0##. What is the total electric field in the space?The Attempt at a Solution By the Gauss law I find that if ##z \geq a## or ##z \leq...
  48. R

    Finding electric potential of two concentric rings

    Homework Statement Two concentric spheres have radii a and b with b>a. The region between them is filled with charge of constant density p. The charge density is zero everywhere else. Hence, find the electric field of all points , then find the electric potential. 2. Homework Equations [/B]The...
  49. anorlunda

    The Perry Report on USA Electric Power

    Find the full text here Staff Report to the Secretary on Electricity Markets and Reliability I really like this report, it's right up my alley. It is professionally done. Every assertion of fact is documented with citations to reputable data sources. I found nothing outrageous in the 187...
  50. C

    Lateral electric fields in a lateral electrostatic actuator

    Hello, I'm reading through section 6.2.2 of https://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-013-electromagnetics-and-applications-spring-2009/readings/MIT6_013S09_chap06.pdf on page 157. I understand all the math, but I have a conceptual questions that I don't seem to...
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