Concept:Parallel conductors carrying electric current exert magnetic forces on one another. The direction of the force depends on the relative directions of the currents.
Formula:$$ \frac{F}{L} = \frac{\mu_0 I_1 I_2}{2\pi d} $$
Solution:- According to the right-hand grip rule, a current produces a concentric magnetic field.
- If currents are in the same direction, the magnetic fields between the wires cancel out (weaker field), causing them to attract.
- If currents are in opposite directions, the magnetic fields between the wires reinforce each other (stronger field), causing the wires to repel.
- Since the question states they repel, they must carry currents in opposite directions.
Why other options are incorrect:Option A leads to attraction. Options C and D result in zero magnetic force because both wires must carry current to produce a mutual magnetic force.
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