contestada

A current I flows down a wire of radius a.
(a) If it is uniformly distributed over the surface, what is the surface current den- sity K?
(b) If it is distributed in such a way that the volume current density is inversely proportional to the distance from the axis, what is J(s)?

Respuesta :

Answer:

Part a)

[tex]K = \frac{I}{\pi a^2}[/tex]

Part b)

[tex]J(s) = \frac{CL}{r}[/tex]

here we know that L = length of the wire

Explanation:

Part a)

Current density is given as

[tex]K = \frac{I}{A}[/tex]

[tex]K = \frac{I}{\pi a^2}[/tex]

since current is uniformly divided across the crossection of the wire so it is given as

[tex]K = \frac{I}{\pi a^2}[/tex]

Part b)

As we know that volume current density is inversely proportional to the distance from the axis

So we will have

[tex]\frac{I}{\pi r^2 L} = \frac{C}{r}[/tex]

so we have

[tex]J(s) = \frac{CL}{r}[/tex]

here we know that L = length of the wire

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