Astrophysics (Index)About

electric field

(electric force as distributed over a space)

An electric field (conventionally termed E in equations) is the tendency at each point in space to force an electrically-charged object in a particular direction, per Coulomb's law. Mathematically, it is a gradient, a function on the three dimensions of space yielding a vector in a direction along the line of the force (which pushes objects of the two polarities in opposite directions along the line) with a magnitude consisting of the amount of force applied to an object at that point per unit mass and unit electric charge of the object. This field is the gradient of a mathematical field, which is termed the field of electric potential.

Two possible mathematical fields describe such a physical field, so by convention, the field is such that the vectors point in the direction that a positively-charged object is pushed. (The other possible mathematical field would just have all the vectors in exactly the opposite direction, showing the direction that a negatively-charged object would be pushed.)

An electric field is analogous to a gravitational field, both following inverse square laws, but incorporates the concept of electric charge with a polarity (positive and negative) and that each polarity attracts the other polarity but repels objects with the same polarity.

Further reading:

Referenced by pages:
CMB polarization
electron screening
electron volt (eV)
field lines
Lorentz force
magnetic dipole radiation
magnetic flux density (B)
mathematical field
Maxwell's equations
particle spectrometer
polarization modes
Poynting vector (S)
Pioneer Venus Orbiter (PVO)
spinning dust emission
Vlasov-Poisson equation