Q 12-06-007NEETNEET 2024Top questionMedium
A sheet is placed on a horizontal surface in front of a strong magnetic pole. A force is needed to :
A. hold the sheet there if it is magnetic.
B. hold the sheet there if it is non-magnetic.
C. move the sheet away from the pole with uniform velocity if it is conducting.
D. move the sheet away from the pole with uniform velocity if it is both, non-conducting and non-polar.
Choose the correct statement(s) from the options given below:
Answer: (D) A and C only
Concept. A force is needed only if there is a magnetic force (on a magnetic sheet) or eddy-current drag (on a conducting sheet moving in a non-uniform field).
Step 1. Check the statements.
- A: a magnetic sheet is attracted, so it must be held ✓.
- B: a non-magnetic sheet feels no force ✗.
- C: a conducting sheet moved away has eddy currents opposing the motion (Lenz) ✓.
- D: a non-conducting, non-magnetic sheet feels nothing ✗.
Answer. A and C only (Option D).
Solution by Sreeraj P, M.Sc Physics