Examples of electric field in the following topics:
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- Electric flux is the rate of flow of the electric field through a given area.
- Electric flux is the rate of flow of the electric field through a given area (see ).
- If the electric field is uniform, the electric flux passing through a surface of vector area S is $\Phi_E = \mathbf{E} \cdot \mathbf{S} = ES \cos \theta$ where E is the magnitude of the electric field (having units of V/m), S is the area of the surface, and θ is the angle between the electric field lines and the normal (perpendicular) to S.
- For a non-uniform electric field, the electric flux dΦE through a small surface area dS is given by $d\Phi_E = \mathbf{E} \cdot d\mathbf{S}$ (the electric field, E, multiplied by the component of area perpendicular to the field).
- The red arrows for the electric field lines.
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- A point charge creates an electric field that can be calculated using Coulomb's law.
- The electric field of a point charge is, like any electric field, a vector field that represents the effect that the point charge has on other charges around it.
- Let's first take a look at the definition of the electric field of a point particle:
- The electric field of a point charge is defined in radial coordinates.
- The electric field of a point charge is symmetric with respect to the θdirection.
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- A point charge creates an electric field that can be calculated using Coulomb's Law.
- The electric field of a point charge is, like any electric field, a vector field that represents the effect that the point charge has on other charges around it.
- Let's first take a look at the definition of electric field of a point particle:
- The electric field of a point charge is defined in radial coordinates.
- The electric field of a point charge is symmetric with respect to the θdirection.
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- An electric field that is uniform is one that reaches the unattainable consistency of being constant throughout.
- A uniform field is that in which the electric field is constant throughout.
- Equations involving non-uniform electric fields require use of differential calculus.
- Uniformity in an electric field can be approximated by placing two conducting plates parallel to one another and creating a potential difference between them.
- Uniformity of an electric field allows for simple calculation of work performed when a test charge is moved across it.
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- Electromagnetic waves are the combination of electric and magnetic field waves produced by moving charges.
- As it travels through space it behaves like a wave, and has an oscillating electric field component and an oscillating magnetic field.
- Once in motion, the electric and magnetic fields created by a charged particle are self-perpetuating—time-dependent changes in one field (electric or magnetic) produce the other.
- This means that an electric field that oscillates as a function of time will produce a magnetic field, and a magnetic field that changes as a function of time will produce an electric field.
- Notice that the electric and magnetic field waves are in phase.
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- In the presence of charge or an electric field, the charges in a conductor will redistribute until they reach static equilibrium.
- If conductors are exposed to charge or an electric field, their internal charges will rearrange rapidly.
- Similarly, if a conductor is placed in an electric field, the charges within the conductor will move until the field is perpendicular to the surface of the conductor.
- Negative charges in the conductor will align themselves towards the positive end of the electric field, leaving positive charges at the negative end of the field.
- This occurrence is similar to that observed in a Faraday cage, which is an enclosure made of a conducting material that shields the inside from an external electric charge or field or shields the outside from an internal electric charge or field.
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- Where F is the force vector, q is the charge, and E is the electric field vector.
- It should be emphasized that the electric force F acts parallel to the electric field E.
- A consequence of this is that the electric field may do work and a charge in a pure electric field will follow the tangent of an electric field line.
- The angle dependence of the magnetic field also causes charged particles to move perpendicular to the magnetic field lines in a circular or helical fashion, while a particle in an electric field will move in a straight line along an electric field line.
- The electric field is directed tangent to the field lines.
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- The electric field is like any other vector field—it exerts a force based on a stimulus, and has units of force times inverse stimulus.
- In the case of an electric field the stimulus is charge, and thus the units are NC-1.
- In other words, the electric field is a measure of force per unit charge.
- In a more pure sense, without assuming field uniformity, electric field is the gradient of the electric potential in the direction of x:
- Explain the relationship between the electric potential and the electric field
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- Thus far, we have looked at electric field lines pertaining to isolated point charges.
- Each will have its own electric field, and the two fields will interact.
- The strength of the electric field depends proportionally upon the separation of the field lines.
- It should also be noted that at any point, the direction of the electric field will be tangent to the field line.
- Example a shows how the electric field is weak between like charges (the concentration of field lines is low between them).
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- Fundamentally, they describe how electric charges and currents create electric and magnetic fields, and how they affect each other.
- Gauss's law relates an electric field to the charge(s) that create(s) it.
- Faraday's law describes how a time-varying magnetic field (or flux) induces an electric field.
- Maxwell added a second source of magnetic fields in his correction: a changing electric field (or flux), which would induce a magnetic field even in the absence of an electrical current.
- He named the changing electric field "displacement current."