Two long parallel wires carry currents in the same direction. They will
Aattract each other
Brepel each other
Cfeel no force
Daccelerate apart
Answer & Solution
Correct answer: A. attract each other
1. The magnetic field at one wire due to the other follows the right-hand rule.
2. Apply F = IL × B at the second wire's location.
3. For parallel currents, the resulting force points toward the other wire.
4. So parallel currents attract; antiparallel currents would repel.
_Source: syllabus Physics Ch 4 "Moving Charges and Magnetism", §4.9_
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