IndietroElectric Potential and Capacitors - Physics
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Termini in questo insieme (20)
Electric potential is the potential for creating electric potential energy if a charge is placed at a given point. It is measured in volts (V), which are joules per coulomb (J/C).
Electric potential energy is the interaction energy of a charged particle with source charges, while electric potential is the potential created by source charges. Potential energy depends on the charge, potential does not.
The unit of electric potential difference is the volt (V), equivalent to joules per coulomb (J/C).
Electric potential increases linearly from the negative plate to the positive plate inside a parallel-plate capacitor.
The electric field is always perpendicular to equipotential surfaces.
Electric field strength \(E\) is given by \(E=\frac{V}{d}\), where \(V\) is the potential difference and \(d\) is the plate separation.
Capacitance is the constant of proportionality between the charge on the capacitor plates and the potential difference between them. Its SI unit is the farad (F).
Inserting a dielectric decreases the electric field and potential difference but increases the capacitance by a factor called the dielectric constant \(\kappa\).
The energy stored is \(U=\frac{1}{2}CV^2\), where \(C\) is capacitance and \(V\) is the voltage.
An electron volt is the kinetic energy gained by an electron accelerating through a potential difference of 1 volt. It is a unit of energy equal to approximately \(1.6 \times 10^{-19}\) joules.
Electric potential at distance \(r\) from a point charge \(q\) is \(V=\frac{kq}{r}\), where \(k\) is Coulomb's constant.
Its electric potential energy decreases and kinetic energy increases; the charge speeds up.
A battery creates a potential difference by chemical separation of charges, typically about 1.5 V for an alkaline battery.
Excess charge resides on the surface, the electric field inside is zero, the exterior field is perpendicular to the surface, and the entire conductor is at the same potential.
The total electric potential at a point is the scalar sum of the potentials due to each individual charge.
Energy density is the energy stored per unit volume in the electric field, with units of joules per cubic meter (J/m³).
Capacitance increases with larger plate area and decreases with greater plate separation.
The charge remains constant and the electric field remains constant.
The charge decreases and the electric field decreases.
Use conservation of energy: kinetic energy change equals charge times potential difference, \(\frac{1}{2}mv_f^2 - \frac{1}{2}mv_i^2 = q(V_i - V_f)\).