Question

6. Consider the two long wires shown. No other sources of magnetic field are nearby. The total magnetic field at some point is measured to be zero. Indicate approximately where this point could be located. Explain your reasoning 10 A Wire A 15 cm Wire B 5 A

Answer 1

Here,

as the current in the wires are in same direction

the point where magnetic field is zero will be in the middle of the two wires

let the point is x from the 10 A wire

for the magnetic field is zero

u0 * 10/(2pi * (x)) - u0 * 5/(2pi * (15 - x)) = 0

10/x - 5/(15 -x) = 0

solving for x

x = 10 cm

the magnetic field is zero in middle of wires at 10 cm from the 10 A wire