Current Density And Charge Density Relationship

The charge density appears in the continuity equation for electric current and also in maxwell s equations.

Current density and charge density relationship. I nae 2 e m. 9 27 2005 charge velocity and current density doc 1 4 jim stiles the univ. J 4 a m 2. Determine the current density when 40 amperes of current is flowing through the battery in a given area of 10 m 2.

This is an adequate description for fields of engineering interest that are produced by aggregates of large numbers of elementary charges. Current density is expressed in a m 2. At a given time t if v is the velocity of the charges at m and da is an infinitesimal surface centred at m and orthogonal to v then during an amount of time dt only the charge contained in the volume formed by da and i. In a thermal expansion density will decrease and temperature increases and vice versa.

The divergence of the electric field at a point in space is equal to the charge density divided by the permittivity of space. V r q v ρ say these charges are moving at velocity ˆ u ua xx. Equation 1 as a simple example assume the current density is uniform equal density across the cross section of a wire with radius r 10 cm. It is given that i 40 a area 10 m 2.

The charge density of molecules impacts chemical and separation processes. As current density is given by j i a refer article of current density conductance and electrical conductivity. The macroscopic theory electric charges deals with continuous charge distributions. Current density calculation example.

The relationship between density and temperature is linear. And resistivity is given by ρ m ne 2 t. It is the principal source term of the electromagnetic field when the charge distribution moves this corresponds to a current density. Suppose that the total current flow is i 3 a.

The current density formula is given by j i a 40 10. Or i a ne 2 e m 1. The total electric current i can be related to the current density j by summing up or integrating the current density over the area where charge is flowing. Of eecs charge velocity and current density consider a small volume v filled with charge q.

By putting above values of j and ρ in equation 1 we get.