Question

Three parallel wires carry the same current in the same direction and are in the same uniform magnetic field. Wire 1 consists of moving electrons, wire 2 consists of moving protons, and wire 3 consists of both electrons and protons, moving in opposite directions. Which of the following is true? The magnetic forces on the three wires are all in the same direction. The magnetic forces on wires 1 and 2 are in the same direction, and the magnetic force on wire 3 is in the opposite direction. The magnetic forces on wires 1 and 3 are in the same direction, and the magnetic force on wire 2 is in the opposite direction. The magnetic forces on wires 2 and 3 are in the same direction, and the magnetic force on wire 1 is in the opposite direction. No two magnetic forces are in the same direction.

Answer 1

When three parallel wires carry the same current in the same direction and are in the same uniform magnetic field, the magnetic forces on wires 1 and 3 are in the same direction, and the magnetic force on wire 2 is in the opposite direction. This is because wire 1 consists of moving electrons, wire 2 consists of moving protons, and wire 3 consists of both electrons and protons moving in opposite directions.

Step-by-step explanation:

When three parallel wires carry the same current in the same direction and are in the same uniform magnetic field, the magnetic forces on wires 1 and 3 are in the same direction, and the magnetic force on wire 2 is in the opposite direction. This is because wire 1 consists of moving electrons, which experience a magnetic force in a certain direction. Wire 3 consists of electrons and protons moving in opposite directions, and the force on the electrons cancels out the force on the protons, resulting in a net force in the same direction as wire 1. Wire 2 consists of moving protons, which experience a magnetic force in the opposite direction. Thus, the magnetic forces on wires 1 and 3 are in the same direction (which is the same as the direction of the magnetic field), and the magnetic force on wire 2 is in the opposite direction.

Answer 2

The correct answer is C: The magnetic forces on wires 1 and 3 are in the same direction, and the magnetic force on wire 2 is in the opposite direction because the magnetic force on a wire is given by the direction of conventional current.

Step-by-step explanation:

When considering three parallel wires carrying the same current in the same direction and placed in the same uniform magnetic field, we must use the right-hand rule to determine the direction of the magnetic force on each wire. Wire 1, consisting of moving electrons, feels a force based on the direction of electron flow; Wire 2, consisting of moving protons, feels a force based on the direction of proton flow, which is the same as conventional current; and Wire 3, with both electrons and protons moving in opposite directions, produces net force where electrons and protons contribute to the resultant force in opposite directions.

However, since magnetic force is on the moving charges and not on the current itself, the direction of the force on a wire is given by the direction of conventional current (opposite to the electron flow), not the actual flow of electrons. Therefore, the magnetic forces on wires 1 and 2 will be in the same direction, since the current is in the same direction, which is opposite to electron flow in wire 1 but in the direction of proton flow in wire 2. Meanwhile, wire 3 experiences the same force direction as wire 1 because the electron current, having a higher magnitude due to the smaller mass and greater mobility of electrons compared to protons, will dominate.

The correct answer to the student's question is: C. The magnetic forces on wires 1 and 3 are in the same direction, and the magnetic force on wire 2 is in the opposite direction.