Two parallel long wires carry currents, $i_1$ and $i_2$ with $i_1>i_2$. When the currents are in same direction, the magnetic field at a point midway between them is 10 μT. If the direction of $i_2$ is reversed, the field becomes 30 μT. The ratio of $i_1/i_2$ is: |
4 : 1 3 : 1 2 : 1 1 : 2 |
2 : 1 |
The correct answer is Option (3) → 2 : 1 |