Question

Figure below shows three long straight wires $P.Q$ and $R$ carrying currents normal to the plane of the paper. All three currents have the same magnitude. Which arrow best shows the direction of the resultant force on the wire $P$?

Answer 1

• Two parallel currents attract each other, and two anti-parallel currents will repel each other.
• So, force between $P$ and $Q$ will be repulsion and force between $P$ and $R$ will be attraction
• The resultant force on $P$ by vector addition is shown in the figure

Hence answer $\left(c\right)$ is correct answer.