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The most familiar non-contact force is gravity, which confers weight. [1] In contrast, a contact force is a force which acts on an object coming physically in contact with it. [1] All four known fundamental interactions are non-contact forces: [2] Gravity, the force of attraction that exists among all bodies that have mass. The force exerted on ...
The electromagnetic force is responsible for many of the chemical and physical phenomena observed in daily life. The electrostatic attraction between atomic nuclei and their electrons holds atoms together. Electric forces also allow different atoms to combine into molecules, including the macromolecules such as proteins that form the basis of life.
The electric field was formally defined as the force exerted per unit charge, but the concept of potential allows for a more useful and equivalent definition: the electric field is the local gradient of the electric potential. Usually expressed in volts per metre, the vector direction of the field is the line of greatest slope of potential, and ...
Electric shock — Physiological reaction of a biological organism to the passage of electric current through its body. Ferranti effect — A rise in the amplitude of the AC voltage at the receiving end of a transmission line , compared with the sending-end voltage, due to the capacitance between the conductors, when the receiving end is open ...
The gravitational and electromagnetic interactions produce long-range forces whose effects can be seen directly in everyday life. The strong and weak interactions produce forces at subatomic scales and govern nuclear interactions inside atoms. Some scientists hypothesize that a fifth force might exist, but these hypotheses remain speculative.
If the electric field in a system can be assumed to result from static charges, that is, a system that exhibits no significant time-varying magnetic fields, the system is justifiably analyzed using only the principles of electrostatics. This is called the "electrostatic approximation". [12]
When talking about electrostatic potential energy, time-invariant electric fields are always assumed so, in this case, the electric field is conservative and Coulomb's law can be used. Using Coulomb's law, it is known that the electrostatic force F and the electric field E created by a discrete point charge Q are radially directed from Q.
The sun's rays can be used to produce electrical energy. The direct user of sunlight is the solar cell or photovoltaic cell, which converts sunlight directly into electrical energy without the incorporation of a mechanical device. This technology is simpler than the fossil-fuel-driven systems of producing electrical energy.