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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 ...
Electrical energy is energy related to forces on electrically charged particles and the movement of those particles (often electrons in wires, but not always). This energy is supplied by the combination of current and electric potential (often referred to as voltage because electric potential is measured in volts) that is delivered by a circuit (e.g., provided by an electric power utility).
The quantity of electric charge can be directly measured with an electrometer, or indirectly measured with a ballistic galvanometer. The elementary charge (the electric charge of the proton) is defined as a fundamental constant in the SI. [7] The value for elementary charge, when expressed in SI units, is exactly 1.602 176 634 × 10 −19 C. [1]
Electric fields are important in many areas of physics, and are exploited in electrical technology. For example, in atomic physics and chemistry , the interaction in the electric field between the atomic nucleus and electrons is the force that holds these particles together in atoms.
Electronic band theory (a branch of physics) explains that electric charge flows when quantum states of matter are available into which electrons can be excited. This allows electrons to gain energy and thereby move through a conductor, such as a metal , if an electric potential difference is applied to the material.
Electric charge is carried by subatomic particles such as electrons and protons. Charged particles can be created and destroyed in elementary particle reactions. In particle physics , charge conservation means that in reactions that create charged particles, equal numbers of positive and negative particles are always created, keeping the net ...
The electron was discovered in 1897 by J. J. Thomson, and it was quickly realized that it was the particle (charge carrier) that carried electric currents in electric circuits. In 1900, the first ( classical ) model of electrical conduction, the Drude model , was proposed by Paul Drude , which finally gave a scientific explanation for Ohm's law.
e is the elementary charge (approximately 1.6 × 10 −19 C) B is the magnetic field (in teslas) m e is the electron mass (approximately 9.1 × 10 −31 kg). The Hall parameter value increases with the magnetic field strength. Physically, the trajectories of electrons are curved by the Lorentz force.