Question

Define current density

Answer 1

HEY.. THERE.. HERE'S YUR ANS..
___________________________
THE amount of electric current flowing per unit cross-sectional area of a material is called current density
•In electromagnetism, current density is the electric current per unit area of cross section. The current density vector is defined as a vector whose magnitude is the electric currentper cross-sectional area at a given point in space, its direction being that of the motion of the charges at this point. In SI units, the electric current density is measured in amperes per square metre The current density vector J is the vector whose magnitude is the electric current density, and whose direction is the same as the motion of the charges at M.
____________________
•At a given time t, if v is the speed 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 l = vdt will flow through dA _________________________________
HOPE IT HELPS U ✌

Answer 2

hey
_________________
____________________

_______Current density or electric current density is related to electromagnetism and is defined as the amount of electric current flowing through a unit cross-sectional area.

It is a vector quantity.

The SI unit of electric current density is ampere per square meter. The symbol "J" is used for electric current density.....
_______________
_________________

______''or

_____________Current density can be expressed by the formula:

J = I / A

where:

J = Electric current density in amperes per sq. meter.

I = Electric current flowing through a given material or a conductor in amperes.

A = Cross-sectional area of a material or a conductor in square meters.

As an example, let us find the current density through a copper wire having a cross-sectional area of 4 square millimeters through which a 6 mA current is flowing. Using the formula J = I/A

Current I = 6 mA = 0.006 A

Area A = 4 sq. mm = 0.004 sq. m

J = I/A = 0.006 Amp / 0.004 sq. m = 1.5 Amp/sq. meter

hope it helps...

____by

_______Roshan