Two infinitely long straight parallel conductors carrying currents I1 and I2 are held at a distance d apart in vacuum. The force F on a length L of one of the conductors due to the other is ________________.
Fill in the blank with the correct answer from the options given below.
1
proportional to L but independent of I1 × I2
2
proportional to I1 × I2 but independent of length L
3
proportional to I1 × I2 × L
4
proportional to \(\rm \frac{L}{I_1\times I_2}\)