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Question #42740
The Question
A rigid rectangular wire loop is placed in a uniform magnetic field perpendicular to its plane, pointing into the page. The loop is divided into two identical adjacent square loops, Loop 1 (left) and Loop 2 (right), by a central straight wire. The side length of each square is (in ). The magnetic field magnitude increases with time as , where is a constant in . The left-most vertical branch has a resistance (in ), and the right-most vertical branch has a resistance (in ). The top and bottom horizontal branches have negligible resistance. The central vertical branch contains an ideal inductor of inductance (in ) and has negligible resistance. Assume the self-inductance of the square loops is negligible compared to . At , the magnetic field starts increasing. Find the magnitude of the current flowing through the central branch as a function of time (in ).
Options
- A.
- B.
- C.
- D.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Multi-Concept_Bridge
Master problems that require linking physics and math concepts to solve complex competitive questions.
Concepts Behind This Question
Kirchhoff’s Junction Rule|Transient Current in RL Circuit|Integration
Why This Question Is Tricky
Common Mistakes
This question tests the application of Kirchhoff's Loop Rule in the presence of non-conservative electric fields.
Students frequently misapply the concept of scalar potential by treating the induced EMFs as lumped batteries that both push current in the same direction through the shared central branch (leading to the incorrect option B).
The trap exploits the failure to recognize that the CCW induced electric field in the right loop actually opposes the CCW field of the left loop within the central branch.
By forcing the transition from algebraic Kirchhoff laws to a system of differential equations governed by Faraday's Law, it rigorously evaluates whether the student correctly integrates the non-conservative field path-dependently.
Quick Facts About This Question
Question Information
| Subject | Physics |
| Chapter | Current Electricity - Class 12 |
| Concept | Kirchhoff’s Junction Rule |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |