In the following figure A, B and C are parallel conductors carrying currents I, I and 2I respectively. Distance between A and B is 1 m and the distance between B and C is also 1 m. $F_1$ is the force exerted by B on A and $F_2$ is the force exerted by C on A. Choose the correct answer.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → $F_1=-F_2$
The force per unit length between two parallel conductors is -
$F=\frac{μ_0I_1I_2}{2\pi d}$
where,
F = force per unit length
$I_1$ and $I_2$ are currents in two conductor
d = Distance between the conductor
$F_1=\frac{μ_0I^2}{2\pi},F_2=-\frac{μ_02I^2}{2\pi×2}=-\frac{μ_0I^2}{2\pi}$
[-ve because currents are flowing in opposite directing]
$∴F_1=-F_2$