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MHT CET 2026 (17 Apr, Shift 1) · Biot-Savart Law & Circular Coils

Biot-Savart Law & Circular Coils question from MHT CET 2026 (17 Apr, Shift 1)

Q9MHT CET 2026 · 17 APR · SHIFT 1Medium

Biot-Savart Law & Circular Coils

The magnetic field at the center of circular coil carrying current 'II' for a single turn of a given length of wire is 'BB'. The same wire is bent in a circular coil having two turns. When the same current passes through it, the value of magnetic field becomes

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Answer: (a)

  1. Fixed wire length LL: nn turns gives r=L2πnr = \frac{L}{2\pi n}, so B=μ0nI2r∝n2B = \frac{\mu_0 n I}{2r} \propto n^2.
  2. nn goes from 1 to 2, so B′=22B=4BB' = 2^2 B = 4B.
  3. So the answer is (a) 4B4B.
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