Derivation of Current Density Formula

The current density formula is derived from the definition of the current density. We know that the current density is defined as the current flowing through the per unit area of the conductor then,

J = dI/dA

where,
dI/dA is the Current change with the unit area.

which implies,

dI = J × dA

dI = J × dAcosθ

when 
dA is perpendicular to J,   (if θ = 90o so, cos θ = 1).

Therefore, 

dI = J × dA

integrating both sides

0 J dI = J × ∫0 A dA

I = J×A

J = I/A

Do Check,

Current Density

Current Density is defined as the amount of current flowing through the per unit area of the wire. It is measured in ampere/m2. Before learning more about current density we have to learn about current. 

Current is defined as the flow of the electron in a wire under a voltage difference. Current is the most common type of energy used in our daily life it provides electrical energy which is responsible for the working of all the electrical appliances which we used in our daily life.

In this article, we will learn about current density, its formula, derivation with brief introduction of electric current.

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