NEET 2025 · PhysicsLoop centre fieldPrevious Year Question
A 2 A current is flowing through two different small circular copper coils having radii ratio 1 : 2. The ratio of their respective magnetic moments will be
- A.2 : 1
- B.4 : 1
- C.1 : 4✓
- D.1 : 2
Correct Answer
(C) 1 : 4
Solution & Explanation
Answer: (C) Solution: Magnetic moment of a single-turn coil: m = I A = I (π r²). Same current for both, so m ∝ r². Ratio = r₁² : r₂² = 1² : 2² = 1 : 4.
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