Two hikers are reading a compass under an overhead transmission line that is 6.4
ID: 2115564 • Letter: T
Question
Two hikers are reading a compass under an overhead transmission line that is 6.40 m above the ground and carries a current of 0.850 kA in a horizontal direction from north to south.1) Find the magnitude of the magnetic field at a point on the ground directly under the transmission line.
2) Where is the magnetic field directed at a point on the ground directly under the transmission line.
3) One hiker suggests that they walk 50.0 m away from the lines to avoid inaccurate compass readings due to the current. Considering that the earth's magnetic field is on the order of 5.00
Explanation / Answer
1) use B=mu0*I/2pir
mu is a constant =4pi*10^-7
in your problem:
I is your current, given in kiloAmps, we want Amps =850 Amps
r is given to you in correct units= 6.40
B=(4pi*10^-7)(850)/2pi(6.4)
B=2.66*10^-5
2) Current is moving north to south, use the right hand rule. Field is pointing east.
3) The field strength is comparable to the Earth's so YES it would.