Two parallel conductors are carrying currents in the same direction. The currents are non-zero and not necessarily equal. The magnitude of the magnetic field midway between them is 40 $\mu$T. If one of the currents then has its direction reversed, what is the resulting magnitude of the magnetic field midway between them?
A) It could be any value.
B) 40$\mu$T
C) a value less than 40 $\mu$T
D) a value greater than 40 $\mu$T

Question

Quizplus · Accepted Answer

When the currents are in the same direction, their magnetic fields at the midpoint add up. Reversing one current causes the fields to subtract, resulting in a greater magnitude than when they were adding.

Two Parallel Conductors Are Carrying Currents in the Same Direction μ\muμ

Two Parallel Conductors Are Carrying Currents in the Same Direction $\mu$