# What is Electric field intensity: Definition and 55 Discussions

An electric field (sometimes E-field) is the physical field that surrounds electrically-charged particles and exerts force on all other charged particles in the field, either attracting or repelling them. It also refers to the physical field for a system of charged particles. Electric fields originate from electric charges, or from time-varying magnetic fields. Electric fields and magnetic fields are both manifestations of the electromagnetic force, one of the four fundamental forces (or interactions) of nature.
Electric fields are important in many areas of physics, and are exploited practically in electrical technology. In atomic physics and chemistry, for instance, the electric field is the attractive force holding the atomic nucleus and electrons together in atoms. It is also the force responsible for chemical bonding between atoms that result in molecules.
Other applications of electric fields include motion detection via electric field proximity sensing and an increasing number of diagnostic and therapeutic medical uses.
The electric field is defined mathematically as a vector field that associates to each point in space the (electrostatic or Coulomb) force per unit of charge exerted on an infinitesimal positive test charge at rest at that point. The derived SI units for the electric field are volts per meter (V/m), exactly equivalent to newtons per coulomb (N/C).

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1. ### Electric field & force due to charged insulating hemispherical shells

So I know I have to equate force on a hemispherical shell with spring force to get value of compression but I can't find the force on the hemispheres Some places that do have the solution use the formula : $$\text{Field of non-conducting hemispherical shell= } \frac{\sigma}{2\epsilon_○}$$ This...
2. ### Maximum charge on a spherical capacitor

The electric field is the one generated by the charge ##+Q## on the inner sphere of the capacitor, which generates a radial electric field ##\vec{E}=\frac{1}{4\pi\varepsilon_0}\frac{Q}{r^2}\hat{r}## which, due to the presence of the dielectric, become...

4. ### Electric Field Intensity: Intersecting E-fields Explained

This the photo of my textbook, Here In the derivation of Electric Field Intensity due to an infinitely long straight uniformly charged wire - In the figure 1(c).20 Vector E1 and vector E2 are electric fields at point P due to the two line elements as shown in the figure 1(c).20. But, in this...
5. ### Find the electric field intensity from an infinite line charge

what I've done so far? -i've determined the vector between the point (4, 0, 0) and the point P. (4, 6, 8) - (4, 0, 0) (0, 6, 8) -The norm of this vector is the radial distance of the line to point P (the value of “ρ” in the formula) √(0^2 + 6^2 + 8^2) = 10 -> ρ = 10 -and its unit vector is...
6. ### What should be the electric field intensity inside a sphere

If the force acting between two point charges were proportional to \frac{1}{r^ 3}, instead of \frac{1}{r^ 2}, what would be the electric field intensity and charge density inside a charged solid metallic sphere?
7. ### Electric field intensity at a distance

Homework Statement Homework EquationsThe Attempt at a Solution The radiations from the bulb spread radially outwards such that "Power at a distance r" = Power radiated/4πr2 . If distance is unchanged and power halved then the intensity should also be halved . From this I get E' = E/2 ...
8. ### Electric Field Intensity of a line on bisecting plane

Homework Statement A very thin, finite, and uniformly charged line of length 10 m carries a charge of 10 µC/m. Calculate the electric field intensity in a plane bisecting the line at ρ = 5 m. Homework EquationsThe Attempt at a Solution Not sure why I'm not getiting this but I've been at this...
9. ### Time period of small oscillations of the point dipole

Homework Statement In an infinite flat layer of thickness 2d, volume charge density is given according to the law: ρ=(ρ°)(x)/d and (-d≤x≤d). Here, x is the axis perpendicular to the plane. In the layer, there is a thin channel in which a point dipole of mass m and dipole moment p is placed...
10. ### Electric field intensity on thin electric sheets

Homework Statement Homework Equations The only equations I can think to use would be: But I'm not sure if they are useful or how they will help. The Attempt at a Solution I have the solution, it just isn't detailed... I don't understand where they get E=1/2ε. Should I be considering...
11. ### How to calculate the Electric Field due to Capacitors?

I have a problem that I have encountered during research. The setup for this scenario is that I am placing two contacts on top of a piece of diamond. What I need to be able to do is calculate the Electric Field at a point within the diamond when I apply a voltage to the contact. The point of...
12. ### Electric field at a point inside of a uniformly charged ball

As the name of the thread says, I am wondering what would the amount and the direction of the electric field at some point in the uniformly charged ball of radius R(it has a constant charge volume density) be at the distance r from the centre of the ball. Does anyone know what would they be? I...
13. ### Electrostatics || A cone charged unifomly, find intensity

Homework Statement A cone of height H and base radius A is charged with charge Q uniformly distributed in all its volume. Find electrostatic field intensity at the top of the cone. DATA: H, A, Q Homework Equations E=ρ/(4πε0) ∫Ω dΩ/R2) and R is a vector (rr^+zz^) r^ and z^ are versors The...
14. ### Electric Field Intensity. Finite sheet of charge.

problem statement, all variables and given/known data A finite sheet of charge, of density ρ=2x(x2+y2+4)^3/2, lies in the z=0 plane for 0≤x≤2m and 0≤y≤2m.Determine E at (0,0,2)m Ans:(18x10^9)(-16/3ax-4ay+8az) Homework Equations E=kQ/R2 The Attempt at a Solution dE=ρdA / R^2 aR...
15. ### Finding electric field intensity

3 point charges q1 q2 & q3 are placed in vacuum as shown. Find electric field intensity at B,if q1=2C,q2=-4C & q3=-2C Homework EquationsThe Attempt at a Solution
16. ### Coulomb's law and Electric field intensity problem

I am not getting the answer to this question as shown in the textbook. Please help...! My attempt is in the last attachment. Thanks.!
17. ### Electric Field Outside a Uniformly Charged Spherical Shell

Homework Statement Show that the electric field E outside a spherical shell of uniform charge density ρs is the same as due to the total charge on the shell located at the centre. Homework Equations Using only Coulomb's Law E=Q/4πε0 ar The Attempt at a Solution If i assumed it as circular...
18. ### Electric Field Intensity and Infinite Sheet Charges

Hey, Just wanted to thank everyone for their time to help solve people problems, I can generally find all my answers here but I made an account now because i can't seem to find a related problem to this. In general the textbook for these types of problems make the plane z=something. In this...
19. ### Do We Use Charge Sign in Electric Field Intensity Formula?

Guys, when utilizing the electric field intensity formula ( Fe=qE), do we use the sign of the charge (q)? I think we do, but I remain confused!
20. ### Spherical Charge Distribution - Electric Field Intensity

Homework Statement A spherical charge distribution is given by p = p_0 (1- \frac{r^2}{a^2}), r\leq a and p = 0, r \gt a , where a is the radius of the sphere. Find the electric field intensity inside the charge distribution. Well I thought I found the answer until I looked at the back of...
21. ### Electric field intensity around a wire

Homework Statement I am trying to calculate the surface charge density and electric field intensity around a copper wire. This is not a part of my assignment but out of curiosity. First, A current carrying wire of radius 2m, radius 0.5cm is at a height of 5cm above a ground plane, the ground...
22. ### Finding the charge density,when Electric field intensity is given.

Homework Statement Given, E=ar20/r2 (mV/m) in free space,find ρv at the point (3,-4,1)(cm). where, ρv=Electric charge density per unit volume E=Electric field intensity Homework Equations ∇.(εE)=ρv The Attempt at a Solution ε∇.E= -2\frac{20ε}{r^3} for point (3,-4,1)(cm)...
23. ### Electric field intensity with a charge decreasing over time

So a lossy dielectric sphere gets an initial charge distribution evenly across the sphere. Find an expression for E inside and outside the sphere for all t. I figured that σ∇E=dp/dt p being volume denity. So I apply spherical coordinates to the div of E and integrate over r to get...
24. ### Relation b/w Electric Field Intensity and Potential Gradient

Homework Statement I don't seem to understand the proper intuition behind the electric field intensity potential difference relation? please can anyone explain it with solid intuition and maybe a good analogy...and can anyone give a short analogy about the concept of electric field...
25. ### Theory about electric field intensity

Homework Statement The electric field intensity at a point between two large parallel plates is 4.8 × 102 N/C. What does the electric field become, as a result of each of the following changes, considered separately (the plates are isolated), (a) when the distance between the plates...
26. ### Electric Field Intensity at a point due to a infinite line charge

Homework Statement Infinite uniform line charges of 5nc/m lie along the (positive and negative) x and y axes in free space. Find E at :P(0,3,4) Homework Equations E due to line charge along the Z-axis is given by: E=(λ/(2∏*ε*r))*ar where λ=line charge density;ε=...
27. ### Calculating Electric Field Strength Between Two Point Charges

A +7.5 nC point charge and a -2.0 point charge are 3.0 cm apart. What is the electric field strength at the midpoint between the two charges? just give me the formula ?
28. ### Electric field intensity inside parallel-plate capacitor filled with water

First, I’d like to say that this is not homework, but my research work. I’ll be very appreciated if someone could help me to address this issue, many thanks in advance. My experimental purpose is to generate uniform electric field inside microchannel by externally-applied electric field...
29. ### Electric field intensity 'inside' a wire carrying current

I am new here and asking question for the first time of course. My question is very simple. Does electric field intensity exist 'inside' a wire carrying current? Please explain the answer.
30. ### Calculating Electric Field Intensity at (0, 0, z)

Homework Statement Electric charge of density ρℓ = 5 μC/m is distributed along the arc r = 2 cm, 0 ≤ ∅ ≤ ∏/4, z = 0. Find the electric ﬁeld intensity at (0, 0, z) Homework Equations dE=(dQ(r)/(4∏ε(r^2))) (unit vector R)The Attempt at a Solution Letting pL be the charge density, letting r^2 =...
31. ### Does Electric Field Intensity Depend on the Separation Distance or the Charge on the Plates?

I have a text that claims that the intensity of the electric field between two parallel plates is independent of the separation distance and depends only on the charge on the plates. Is this correct?
32. ### Difference between electric field intensity of plane and conducting sheet

what is the difference between the electric field intensity of 1)infinite plane charged sheet whose formula is E=\sigma/2\epsilono and 2)infinite conducting charged sheet whose formula is E = \sigma/\epsilono
33. ### Electrostatics - calculation of electric field intensity

electrostatics --- calculation of electric field intensity Homework Statement My aim is to calculate electric field intensity at a point P where the test charge qo is kept which is at a distance r from the source charge q is kept. Homework Equations Why it has mentioned limit qo...
34. ### Find the electric field intensity at point D

[b]1. The problem statement, all variables and given/knownThe diagram shows three small charges at three corners of a rectangle; charge A is -12µC, charge B is -15µC and charge C is +8.1µC. Calculate the magnitude and direction of the electric field intensity at the fourth corner, D. The...
35. ### Electric Scalar Potential and Electric Field Intensity

Homework Statement A uniform line charge of -4π x 8.85 pCm^-1 is situated between the points (-5,0) and (-2,0) m and another such line of positive charge between (2,0) and (5,0) m. A) Find the electric scalar potential V at (1,0) m. B) Find the electric field intensity E at the same...
36. ### Finding electric field intensity, power, current given current density

Homework Statement Sheet of wire is biased with an electrical potential at each end of conduct current. Given current density, J, in wire: J=-x2y ax +xz ay + 2xyz az A)Continuity equation to prove its possible B) current along length of wire C) Electric field intensity E D) voltage drop...
37. ### Finding Electric Field intensity

Homework Statement A proton traveling along the x-axis is slowed by a uniform electric field E. At x = 20 cm, the proton has a speed of 3.5 x 106 ms-1 and at x = 80 cm, its speed is zero. Find the magnitude and direction of electric field intensity. Can someone please! check my procedure...
38. ### Understanding Electric Field Intensity of Point Charges

Why do we take a point charge always while estimating the electric field intensity of a system of charge? as in Coulomb's and Gauss's Law etc.
39. ### Electric Flux Density / Electric Field Intensity

Hey people, I'm struggling to understand exactly what Electric Flux Density D and Electric Field Intensity E are. So far, my understanding is that D depends on relative permittivity, while E depends only on the permittivity of free space. Also, I understand that D reflects only the free...
40. ### Relationship between electric field intensity and potential

I find that there are two ways in which the relationship between electric field intensity and potential are expressed as mentioned hereunder: (A) E = - dV / dx (V = potential and x is the direction along which V varies) (B) E = - Delta V / Delta x My understanding of the application of...
41. ### 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...
42. ### What is the electric field intensity at point A due to two point charges?

Homework Statement Find Enet (magnitude and direction) at point A and include a vector diagram. q1 = 2.0x10^-6 C q2 = 6.0x10^-6 C r1 = 2.5x10^-3 m r2 = 1.7x10^-3 m Homework Equations E = Klql/r^2 or E = Kq/r^2 (the first equation just has absolute values around the q for reminder...
43. ### Optimizing radius for minimus electric field intensity

Homework Statement Assume a spherical electrode of radius r1 and a spherical metal tank of radius r2. The electrode is inside the metal tank. The electrode must operate at a voltage V with respect to a tank. The tank is grounded (V=0). Now let's focus on the electric field intensity at the...
44. ### How Does Charge Distribution Affect Electric Field Intensity at the Origin?

Homework Statement A rod of length l with a uniform charge per unit length lambda is placed a distance d from the origin along the x axis. A similar rod with the same charge is placed along the y axis. Determine the net electric field intensity at the origin.Homework Equations Electric Field...
45. ### Calculating Electric Field Intensity with Two Spherical Shells

Hi Two spherical shells where the inner has a radius a and the outer a radius of b. The inner has a total charge of -Q whereas the outer shell has a total charge +Q. The question is to calculate the electric field intensity everywhere in space. My question is now, how do I choose the limits...
46. ### Point-Plane Electric Field Intensity

Hi folks. I have read in several papers that the electric field intensity adjacent to the very tip of an electrode (the "point" in a point-plane geometry) surrounded by a dielectric medium is given by 2V / [r ln(4d/r)] where r is the tip radius, d is the point-plane spacing, and V is...
47. ### Electric field intensity/ charge magnitude question

Homework Statement Two equal but oppositely charged points are 1.0 m apart in a vacuum. The electric field intensity at the midpoint between the charges is 2.4x10^5 N/C. What is the magnitude of each charge? Homework Equations Electric force= Kc (q/r^2) Kc=8.99x10^9 The Attempt at...
48. ### Why is the electric field intensity zero at only one point?

Suppose you have a Cartesian coordinate system with: a 2uC charge at (0,0) and a -8uC charge at (4,0), why is there only one point in which the EFI is zero (-4,0)? Shouldn't that be the first point where the EFI is zero (so (-5,0),(-6,0)... all have Electric Fields of zero) The reason I...
49. ### Charge and Electric Field Intensity

If there are two bodies, such as a sphere and a thin rod (each with exactly the same charge), why does the sphere have a greater electric field intensity? Are there any other variables that influence the electric field intensity if the charge is not an ultimate dependent factor? If the...
50. ### E&M - Electric Field Intensity in Microwave

Hi, This problem has me stumped and I keep thinking that I'm missing something simple. The question gives us a simple model for modelling a microwave. We consider a plane wave traveling through an object in the microwave (in the z direction), with no reflection. So, the general form should be...