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Question #43338
The Question
A series LCR circuit consists of a capacitor of capacitance , an inductor of effective inductance with a ferromagnetic core, and an ohmic resistance . The circuit is driven by an AC voltage source at its resonant frequency, maintaining a peak steady-state current . The ferromagnetic core has a volume and the area of its magnetic hysteresis loop ( curve) is . What is the effective quality factor of this circuit?
Options
- A.
25
- B.
50
- C.
75
- D.
100
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Variable_Constraint
Develop pure symbolic logic skills by mastering algebraic constraints without relying on numerical data.
Concepts Behind This Question
Quality Factor (Q-factor)|Hysteresis Loop Area|Average Power over Cycle
Why This Question Is Tricky
Common Mistakes
This question tests the fundamental energy-based definition of the Quality Factor (Q-factor) and the physical reality of core losses in AC circuits.
Students are heavily conditioned to blindly apply the lumped-parameter formula , which yields (Option D).
This formula assumes that all energy dissipation is purely ohmic.
However, in a real inductor with a ferromagnetic core, the hysteresis loop area represents an additional, frequency-dependent energy loss per cycle.
To solve this correctly, the student must abandon the standard formula, calculate the total energy dissipated per cycle (ohmic + hysteresis), and use the foundational definition .
This effectively models the hysteresis as an equivalent series resistance .
Quick Facts About This Question
Question Information
| Subject | Physics |
| Chapter | Alternating Current - Class 12 |
| Concept | Quality Factor (Q-factor) |
| Difficulty | 8 |
| Cognitive Load | 7 |
| Target Solve Time | 160 sec |
| Access | Free |