The force between two long parallel conductors is inversely proportional to the distance between the conductors. Therefore, the correct answer is C: “distance between the conductors.”
Here’s a further explanation:
The force between two long parallel conductors is governed by Ampere’s law and the Biot-Savart law, which describe the magnetic fields produced by the currents in the conductors.
According to these laws, the force per unit length (F) between two parallel conductors is directly proportional to the product of the currents (I1 and I2) in the conductors and inversely proportional to the distance (d) between them. Mathematically, it can be expressed as:
F ∝ (I1 * I2) / d
This equation shows that the force between the conductors is inversely proportional to the distance between them. As the distance increases, the force decreases, and as the distance decreases, the force increases.
The other options mentioned are not directly related to the force between the conductors:
The radius of the conductors (option A) does not affect the force between them as long as the currents flow in the same cross-sectional area.
The current in one conductor (option B) affects the magnitude of the force but is not inversely proportional to it.
The product of the currents in two conductors (option D) affects the magnitude of the force, but it is not inversely proportional to it.
Therefore, the correct answer is C: “distance between the conductors.”