Two identical coils are parallel to each other on the same axis. They are separated by a distance equal to their radius. They each have N turns and carry equal currents I in the same direction. Calculate the field strength on the axis at the midpoint between the two loops if the loops are 10 cm in diameter, have 10 turns, and carry a current of 1.0 A

This just equates to zero doesn't it? Since the current is going in the same direction wouldn't the field strength at the midpoint between coils be zero?

Question

Two identical coils are parallel to each other on the same axis. They are separated by a distance equal to their radius. They each have N turns and carry equal currents I in the same direction. Calculate the field strength on the axis at the midpoint between the two loops if the loops are 10 cm in diameter, have 10 turns, and carry a current of 1.0 A

This just equates to zero doesn't it? Since the current is going in the same direction wouldn't the field strength at the midpoint between coils be zero?

anonymous · Answer

Yes. Your intuition is correct. But keep in mind that these are straight wires but solenoids. The field strength outside of a solenoid is nearly zero, but what little field is there will be cancelled out by the parallel, same direction current.