Question

Four long straight parallel wires are oriented perpendicular to the x-y plane and carry currents I₁, I₂, I₃ and I₄. The magnitudes of the currents are all identical and equal to 8.475 A. Current I₄ is into the x-y plane (i.e. into the screen), whereas each of the other three currents are all out of the x-y plane(i.e. out of the screen) as shown below. Each of the wires is a distance of 6.105 cm from the origin as measured in the x-y plane.

Х 14 12 13 :

Part A) What is the magnitude of the net magnetic field at the origin due to the four current carrying wires?

Part B) The direction of the net magnetic field at the origin due to the currents flowing in the four wires is..?

Answer 1

field due to i1 is equal and acts opposite to field due to i3, hence they cancel each other.

so the net field is given by the sum of fields due to i2 and i4

B = (uo/4pi) 2 ( i + i) / r

B = 10^-7* 2*2* 8.475 / 0.06105

B = 5.553* 10^-5 T

directed along - y axis

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