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MHT CET 2026 (20 Apr, Shift 2) · Current Loop as a Magnetic Dipole

Current Loop as a Magnetic Dipole question from MHT CET 2026 (20 Apr, Shift 2)

Q6MHT CET 2026 · 20 APR · SHIFT 2Medium

Current Loop as a Magnetic Dipole

A thin circular wire carrying current II has magnetic moment MM. The shape of the wire is changed to a square and it carries the same current. It will have magnetic moment M1M_1. The ratio MM to M1M_1 is

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Answer: (b)

  1. Same wire length LL, same current, so M∝M \propto area.
  2. Circle: 2πr=L⇒A=πr2=L24π2\pi r = L \Rightarrow A = \pi r^2 = \frac{L^2}{4\pi}.
  3. Square: side L4⇒A=L216\frac{L}{4} \Rightarrow A = \frac{L^2}{16}.
  4. MM1=164π=4π\frac{M}{M_1} = \frac{16}{4\pi} = \frac{4}{\pi}, so the answer is (b).
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