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Question #43402
The Question
A rigid circular wire loop of radius and cross-sectional area lies in the plane, centered at the origin. The wire contains a free electron density , and the electrons have a relaxation time and mass . A uniform azimuthal electric field is established in the wire, driving a steady base conventional current in the counter-clockwise direction (). The entire loop is placed inside a rocket that is accelerating with a constant acceleration relative to an inertial frame. Assuming steady state is reached in the rocket's frame, find the net magnetic field at a point on the axis of the loop. (Given: is the magnitude of the elementary charge, is the vacuum permeability. Ignore the self-magnetic field's effect on the drift velocity).
Options
- A.
- B.
- C.
- D.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Intuition_Breaker
Train your brain to resist "obvious" answers that are designed to deceive your intuition.
Concepts Behind This Question
Magnetic Field on Axis vs. Center|Pseudo Force Directionality|Vector Cross-Products
Why This Question Is Tricky
Common Mistakes
This question tests the coupling of non-inertial mechanics with electrodynamics via the Drude model.
Students commonly fall into the trap of treating current as a rigid, scalar property (Option D), ignoring that charge carriers possess mass and are subject to pseudo-forces in an accelerating frame.
Even if the pseudo-force is recognized, a secondary trap lies in the sign convention: failing to account for the electron's negative charge when converting drift velocity to conventional current leads to an inverted transverse field (Option B).
Finally, the problem forces the abandonment of the standard axial Biot-Savart formula, requiring a full vector path integral to reveal the symmetry-breaking transverse magnetic field component () generated by the acceleration.
Quick Facts About This Question
Question Information
| Subject | Physics |
| Chapter | Moving Charges and Magnetism - Class 12 |
| Concept | Magnetic Field on Axis vs. Center |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |