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The north pole of a magnet is falling towards a metallic ring, as shown in the figure. The direction of the induced current in the ring, if looked at from above, will be ______.

Asked in GUJCET 2008 · Direction of the induced current

• (1) anticlockwise
• (2) clockwise
• (3) clockwise or anticlockwise, depending on the metal of the ring
• (4) no induced current

Step-by-step solution

Why the other options are wrong

• (2) A clockwise current, seen from above, would make the ring's upper face a south pole. That would attract the falling north pole and speed it up, creating energy from nothing, which Lenz's law forbids.
• (3) The metal changes only how large the current is, through its resistance. The direction is fixed by Lenz's law for every conductor.
• (4) The flux through the ring grows as the magnet approaches, and a changing flux through a closed conductor always drives a current.

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