# Problem: Although the evidence is weak, there has been concern in recent years over possible health effects from the magnetic fields generated by transmission lines. A typical high-voltage transmission line is 20 m off the ground and carries a current of 200 A. A. Estimate the magnetic field strength on the ground underneath such a line. B. What percentage of the earth’s magnetic field does this represent?

###### FREE Expert Solution

Magnetic field around a wire carrying current:

$\overline{){\mathbf{B}}{\mathbf{=}}\frac{{\mathbf{\mu }}_{\mathbf{0}}\mathbf{i}}{\mathbf{2}\mathbf{\pi }\mathbf{r}}}$

85% (134 ratings) ###### Problem Details

Although the evidence is weak, there has been concern in recent years over possible health effects from the magnetic fields generated by transmission lines. A typical high-voltage transmission line is 20 m off the ground and carries a current of 200 A.

A. Estimate the magnetic field strength on the ground underneath such a line.

B. What percentage of the earth’s magnetic field does this represent?