Physics
Physics
Problem
A horizontal circular loop lies on a table. A uniform magnetic field directed vertically upward through the loop increases in magnitude with time. Seen from above, the induced current in the loop will flow a) anticlockwise b) no current is induced c) clockwise d) first clockwise then anticlockwiseIntuitive explanation
The key is Faraday's law and Lenz's law working together. As the upward magnetic field strengthens, the magnetic flux through the loop increases. By Lenz's law, the induced current must create its own magnetic field to oppose this change—meaning it generates a field pointing downward through the loop. Using the right-hand rule, a downward field requires the current to flow clockwise when viewed from above.
Intuitive explanation
The key is Faraday's law and Lenz's law working together. As the upward magnetic field strengthens, the magnetic flux through the loop increases. By Lenz's law, the induced current must create its own magnetic field to oppose this change—meaning it generates a field pointing downward through the loop. Using the right-hand rule, a downward field requires the current to flow clockwise when viewed from above.