The measure of the amount of electric charge per unit time that flows through the unit area of the cross-section. The Current density is a vector quantity. Therefore, it has both magnitude and direction. The S.I unit of Current density is A/m2 and is denoted by the symbol J.
Current Density Formula is expressed as,
J = I / A
I denote the current flowing through the conductor in Amperes and
A denotes the cross-section area in m2
Current density is expressed in A/m2
A 5 mm2 copper wire has a current of 5 mA of current flowing through it. Determine the current density.
Total Current I is 5 mA
Total Area A is 5 mm2
The Current density J = I / A
= 5×10−3 / 5×10−3
= 1 A/m2
Determine the current density of if 50 Amperes of current flows through the battery in an area of 10 m2?
Current I is 50 A,
Area A is 10 m2
The current density is given by J = 50 / 10
J= 5 A/m2.