A small coil lies inside a large coil. The two coils are horizontal concentric and carry currents in opposite directions. The large coil will experience______________?
Correct answer: D. No resultant force
- A. A torque about horizontal axis
- B. A torque about vertical axis
- C. An upward force along the axis
- D. No resultant force
Explanation
Opposite currents make the coaxial coils repel, but with the small coil exactly concentric and centered, the forces on opposite sides cancel. Hence the large coil has no resultant force and no torque, although internal mechanical stresses exist.
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