JEE Advanced 2020Paper 1
- Exam
- JEE Advanced
- Year
- 2020
- Paper
- Paper 1
- Subject
- Physics
- Chapter
- Electromagnetic Induction
JEE Advanced 2020 · Paper 1 · Physics · Electromagnetic Induction
A light disc made of aluminum (a nonmagnetic material) is kept...
A light disc made of aluminum (a nonmagnetic material) is kept horizontally and is free to rotate about its axis as shown in the figure. A strong magnet is held vertically at a point above the disc away from its axis. On revolving the magnet about the axis of the disc, the disc will (figure is schematic and not drawn to scale)
Options
- Arotate in the direction opposite to the direction of magnet's motion
- Brotate in the same direction as the direction of magnet's motion
- Cnot rotate and its temperature will remain unchanged
- Dnot rotate but its temperature will slowly rise
Correct answer
B. rotate in the same direction as the direction of magnet's motion
Step-by-step solution
When we start rotating the magnet above the disc, eddy currents will be generated in the disc. Now we know from Lenz's law that the induced emf will drive the current such that it opposes the cause of the production of induced emf. Hence the disc will rotate in the same direction as the direction of magnet's motion