In: Physics
A long pair of isolated wires provides a device with 12.5A direct current as input / output. If the diameters of the wires are negligible, but if there is a 2.8mm gap with each other, calculate the magnitude of the magnetic field at a distance of 10cm from the middle point of this gap and compare it with the magnetic field of the world and discuss your result.
The system:
Here,
and
The magnitude of magnetic field due to wire carrying current I at a distance r from Biot-Savart Law:
Magnetic field due to wire 1:
Magnetic field due to wire 2:
The wires carry current in opposite direction (since it is an input output system), so the magnetic fields oppose each other.
Therefore, the total magnetic field.
Plugging in all the values,
Converting to gauss,
The magnetic field of the earth, is compared to this is much higher.
The magnetic field of the earth is about 0.25 gauss.
Due to the given system, the magnetic field is of the order of milligauss, whereas the earth's magnetic field is of the order of 0.1 gauss.
It is higher by a factor of 0.25/0.007=35.7.