Two identical coaxial circular loops carry equal currents in the same direction. If the loops approach each other the current in______________?
Correct answer: B. Each decrease
- A. Each increase
- B. Each decrease
- C. Each remains the same
- D. One increases whereas that in the other decreases
Explanation
As the loops approach, the magnetic flux through each loop increases. By Lenz's law, the induced effect opposes this increase, producing a current opposite to the original current and reducing the current in each loop, assuming identical driven circuits. Students may choose a by thinking that closer loops reinforce one another without considering the opposing induced current.
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About Lenz's Law
Lenz's law states that the induced current flows in a direction that opposes the change in magnetic flux producing it. Questions connect this rule with Faraday's law, magnetic flux, induced emf and the direction of motion or current, while distinguishing opposition to flux change from opposition to the magnetic field itself.
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