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No actual charge is transported through the vacuum between its plates. Nonetheless, a magnetic field exists between the plates as though a current were present there as well. One explanation is that a displacement current I D "flows" in the vacuum, and this current produces the magnetic field in the region between the plates according to ...
Continuous charge distribution. The volume charge density ρ is the amount of charge per unit volume (cube), surface charge density σ is amount per unit surface area (circle) with outward unit normal n̂, d is the dipole moment between two point charges, the volume density of these is the polarization density P.
The formula provides a natural generalization of the Coulomb's law for cases where the source charge is moving: = [′ ′ + ′ (′ ′) + ′] = ′ Here, and are the electric and magnetic fields respectively, is the electric charge, is the vacuum permittivity (electric field constant) and is the speed of light.
The shear rate for a fluid flowing between two parallel plates, one moving at a constant speed and the other one stationary (Couette flow), is defined by ˙ =, where: ˙ is the shear rate, measured in reciprocal seconds;
The DH equation can be solved exactly for two plates. [ 1 ] [ 5 ] The boundary conditions play an important role, and the surface potential and surface charge density ψ ¯ D {\displaystyle {\bar {\psi }}_{\rm {D}}} and σ ¯ {\displaystyle {\bar {\sigma }}} become functions of the surface separation h and they may differ from the corresponding ...
The work per unit of charge is defined by moving a negligible test charge between two points, and is expressed as the difference in electric potential at those points. The work can be done, for example, by electrochemical devices ( electrochemical cells ) or different metals junctions [ clarification needed ] generating an electromotive force .
The two charge carriers, electrons and holes, will typically have different drift velocities for the same electric field. Quasi-ballistic transport is possible in solids if the electrons are accelerated across a very small distance (as small as the mean free path), or for a very short time (as short as the mean free time). In these cases, drift ...
Consider a capacitor of capacitance C, holding a charge +q on one plate and −q on the other. Moving a small element of charge dq from one plate to the other against the potential difference V = q/C requires the work dW: =, where W is the work measured in joules, q is the charge measured in coulombs and C is the capacitance, measured in farads.