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Formula Current-Carrying Wire (Inside) Electric current    Radius    Distance   

Formula
Formula: Current-Carrying Wire (Inside)
Magnetic Field Inside and Outside a Cylinder (Graph)

Magnetic field

Unit
Magnetic field inside the wire increases linearly with the distance to the center of the wire. The B field runs in cylindrical coordinates in the \(\varphi\) direction.

Electric current

Unit
Current in the long straight wire.

Radius

Unit
Radius of the long straight wire.

Distance

Unit
Distance from the center of the wire to a location \(r\) inside the wire where the magnetic field is to be calculated. Here the formula is valid only for inside the wire: \( r ~\le~ R \).

Vacuum permeability

Unit
Vacuum permeability is a physical constant with the value: \( \mu_0 = 4\pi \cdot 10^{-7} \, \frac{ \text{N} }{ \text{A}^2 } \).