# What is Electric feild: Definition and 20 Discussions

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1. ### I Do equipotential lines fall on the equiprobability contours?

For 2D charge distribution ρ(x,y)=Ne PDF(x,y), where PDF is the normalized probability density function with its peak on (0,0) and has standard deviations σ x. and σ y. Are the contours with the equal probability "PDF(x,y)=const" the same as the equipotiential contours?, I tend to think that...
2. ### Help me find the electric field vector

I have these equations in my book, but I don't know how I can use them in this problem Electric field of a plane has surface electric density σ: E = σ/2εε₀ Ostrogradski - Gauss theorem: Φ₀ = integral DdS Can someone help me :((
3. ### Current and stationary charges

I've learned that moving charges produce magnetic fields which in turn affect other charges in motion. After seeing explanations that point to special relativity, I am kind of confused. Can **ALL** magnetic fields be accounted as some kind of electric field from a particular reference frame...
4. ### How can I plot the electric field vs position for two charges?

Homework Statement :- electric field vs position how to plot it[/B]Homework Equations :- force per unit charge[/B]The Attempt at a Solution :- i know option 1 and 2 can never be an answer to this question but still i am confused between 3 and 4 option and help me solve with proper equation[/B]
5. ### Non-conductve sphere with cavity -- find Electric field

I have a non conducting sphere with a charge ρ=A/r per uni vollume A is constant. suppose there is a cavity in the centre and within a particle of charge q. i want to find the E inside the sphere in respect with r. Homework EquationsThe Attempt at a Solution for radius equal of the cavity i get...
6. ### Induced EMF in a coil outside a solenoid

Homework Statement [/B] A conducting coil of radius R is outside a long solenoid with a cross section of radius r. What is the emf induced in the coil? Most example problems of this type I think are solved based on Faraday’s Law. These examples do not use the distance from the solenoid to the...
7. ### Help finding the electric feild strength in a uniform E-field

Homework Statement The voltage across a membrane forming a cell wall is 78.7 mV and the membrane is 8.52 nm thick. What is the electric field strength? (The value is surprisingly large, but correct.) You may assume a uniform E-field. Homework Equations E=-Vd The Attempt at a Solution...
8. ### Energy associated with electric feild.

Homework Statement a conducting sphere of radius R has charge +Q on its surface. if the charge on the sphere is doubled and radius is halved, the energy associated with the electric field will be? Homework Equations electric field = K * Q/(R*R) Energy associated with field will...
9. ### Find the current that flows (electric feild)

Homework Statement 2 spheres at a potential diff V what current flows from one to the other Homework Equations I=\intj.da The Attempt at a Solution My question is about finding the electric field. I thought it would be E=\sigma/\epsilon but they have it has E= Q/4\pir2\epsilon...
10. ### Electric charge and electric feild prblem

Homework Statement A charge of 6.00 mC is placed at each corner of a square 0.100 m on a side. Determine the magnitude abd direction of the force on each charge. Homework Equations The Attempt at a Solution
11. ### Electric Field Sketch: Ex vs. x & Fx vs. x Homework

Homework Statement Sketch 2 diagrams 1 showing Ex against x and 1 showing Fx against x Homework Equations The Attempt at a Solution I have drawn a graph showing potential difference against x and have been asked to produce a sketch showing Ex and Fx relating to this graph but I am...
12. ### Conservation of electric feild

1. In the figure below, short sections of two very long parallel lines of charge are shown, fixed in place and separated by L = 8.0 cm. The uniform linear charge densities are +5.8 µC/m for line 1 and -2.0 µC/m for line 2. Where along the x-axis shown is the net electric field from the two lines...
13. ### Electric feild and a conducter

Homework Statement The problem shows a picture of a spherical conductor that is placed some distance away from a positive charge. It wants me to draw in how I think the charge will be distributed. Homework Equations E=(KQq)/r^(2) The Attempt at a Solution My original thoughts...
14. ### Relating Electric Feild and Electric Potential

Looking at the equations for electric field and for electric potential: The electric field equation: E = 4*pi*k*sigma / (- (base zero) The electric potential equation: /\U (base E) = -W(base E) = -q*E*d /\ - delta Could someone help me figure out their relationship? I am...
15. ### Electric Feild Causing a Spark.

Homework Statement Approximately how large an electric field would be required to cause a spark in a gas at standard temperature and pressure if the ionization energy for the molecule of this gas is 1.5 times the ionization energy for air molecules, and the cross-sectional area of the molecules...
16. ### Electric Feild and Capacitance

Homework Statement A homemade capacitor is assembled by placing two 9inch pie pants 5cm apart and connecting them to the opposite terminals of a 9V battery. Estimate A) the capacitance, B) the charge on each plate c) the electric field halfway between the plates d) the work done by the battery...
17. ### How Is the Net Charge Calculated in a Cube Within a Vertical Electric Field?

In a region of fair weather, the electric field is found to be vertically down. At an altitude of 400m E=20 N/C at 200m E=90 N/C. Find the net charge contained in a cube 200m on and edge, with horizontal faces at altititudes of 200m and 400m. I wasn't sure where to start so i used coulumbs...
18. ### Electric Field of 90° Arc of 2 Wires w/ Uniform Charge - Q/πR^2

two wires in the shape of a 9o degrees circular arc of radius R have charges +(-) Q distributed uniformly on them. They are positioned opposite each other in the second and 4th quadrants. Show that the electric field at the origin is \frac{4kQ}{\pi R^2} I tried starting with the electric...
19. ### Yet another electric feild problem

This one I'm having a bit of conceptual difficulty with. Problem is: three positive point charges, q, are placed in an equal lateral triangle, charges being the vertex's. Length of one side is a. Calculate the electric field at point P, which is also the the location of the topmost charge...
20. ### Electricity & Magnetism: Help With 2 Homework Problems

I just recently began the Electricity and Magnetism course. Having said that I'm requesting help with a general plan of attack for two homework problems, that is, conceptually understanding how to use the math on these problems. First problems states there is a hollow cylinder of length h...