Equipotential surfaces are a concept applicable to any potential vector field , for example, to a static electric field or to a Newtonian gravitational field . The equipotential surface is the surface on which the scalar potential of a given potential field takes a constant value ( surface of the potential level ). Another equivalent definition is a surface, at any point orthogonal to the lines of force of the field .
The conductor surface in electrostatics is an equipotential surface. In addition, placing the conductor on an equipotential surface does not cause a change in the configuration of the electrostatic field. This fact is used in the image method , which allows to calculate the electrostatic field for complex configurations.
In the (stationary) gravitational field, the level of a stationary fluid is set at an equipotential surface. In particular, it is approximately possible to assert that the level of the oceans passes along the equipotential surface of the Earth's gravitational field [1] . The shape of the surface of the oceans [2] , extended to the surface of the Earth , is called a geoid and plays an important role in geodesy . A geoid is thus an equipotential surface of gravity , consisting of a gravitational and centrifugal component.
Notes
- ↑ The inaccuracy of this statement is related to two unrecorded impacts: 1) the so-called tidal forces from other celestial bodies, primarily the Moon and the Sun, 2) the rotation of the earth. Accounting for the first impact is rather complicated primarily because of its nonstationarity (the water of the oceans, having inertia, does not immediately react to such an impact, which greatly complicates the task, besides taking it beyond the scope of equipotential surfaces). Taking into account the second impact is not beyond the scope of this topic, in order to take it into account, it is enough to consider in the non-inertial (rotating) reference system associated with the Earth, and instead of the pure potential of the gravitational field, consider the total potential of the gravitational field and centrifugal force (correction from the second is not great, but noticeable): it is the equipotential surface of this total potential that will give in a very good approximation the shape of the surface of the oceans in neglect of tidal forces from other celestial bodies, the cat Paradise will also be comparatively good estimate averaged over the ebb and flow of the ocean's surface shape.
- ↑ Being some equipotential surface, in the sense and approximation, described in more detail above.
Links
- Soviet Encyclopedic Dictionary, 4th ed., 1989.
- Elementary textbook of Physics edited by Academician G. S. Landsberg, Volume II.