Field (physics)

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![The E fields and B fields due to electric charges (black/white) and magnetic poles (red/blue).[11][12] Top: E field due to an electric dipole moment d. Bottom left: B field due to a mathematical magnetic dipole m formed by two magnetic monopoles. Bottom right: B field due to a pure magnetic dipole moment m found in ordinary matter (not from monopoles).](/uploads/202502/13/Em_dipoles.svg1833.png)
![The E fields and B fields due to electric charges (black/white) and magnetic poles (red/blue).[11][12] E fields due to stationary electric charges and B fields due to stationary magnetic charges (note in nature N and S monopoles do not exist). In motion (velocity v), an electric charge induces a B field while a magnetic charge (not found in nature) would induce an E field. Conventional current is used.](/uploads/202502/13/Em_monopoles.svg1833.png)
In physics, a field is a physical quantity that has a value for each point in space and time. For example, on a weather map, the surface wind velocity is described by assigning a vector to each point on a map. Each vector represents the speed and direction of the movement of air at that point. As another example, an electric field can be thought of as a "condition in space" emanating from an electric charge and extending throughout the whole of space. When a test electric charge is placed in this electric field, the particle accelerates due to a force. Physicists have found the notion of a field to be of such practical utility for the analysis of forces that they have come to think of a force as due to a field.