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 . part a estimate the magnetic field strength on the ground underneath such a line. express your answer in microtesla. b b = nothing μt submitrequest answer part b what percentage of the earth’s magnetic field does this represent? (assume that magnetic field strength at the surface of the earth is 5× 10 −5 t ) express your answer in percent. b tl b earth b t l b e a r t h = nothing % submitrequest answer provide feedback next

A)

The magnetic field strength around a current-carrying wire is given by the formula

where

is the vacuum permeability

I is the current in the wire

r is the radial distance from the wire

In this problem, we have

I = 200 A is the current in the wire

and we want to calculate the magnetic field strength at a distance of

r = 20 m

from the wire, so:

B) 4 %

The magnetic field strength at the surface of the Earth is

While the strength of the magnetic field generated by the wire at ground level is

Therefore, in percentage, it is:

answer; (d) spontaneous processes are characterized by the overall conversion of order to disorder;

i am pretty sure it is c because when people are closer together, they cannot move as freely. picture being in a mostly full elevator, for instance. the people are right next to you, and you can barely move.