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JEE Main 2026 (4 Apr, Shift 2) · Current Loop as a Magnetic Dipole

Current Loop as a Magnetic Dipole question from JEE Main 2026 (4 Apr, Shift 2)

Q16JEE Main 2026 · 4 APR · SHIFT 2Medium

Current Loop as a Magnetic Dipole

A circular coil of radius 2 cm and 125 turns carries a current of 1 A. The coil is placed in a uniform magnetic field of magnitude 0.4 T. The axis of the coil makes an angle of 30∘30^\circ with the direction of the magnetic field. The torque acting on the coil is α×10−4 N.m\alpha \times 10^{-4}\text{ N.m}. The value of α\alpha is . (π=3.14)\rule{2em}{0.4pt}.\ (\pi = 3.14)

Numerical answer type. Work it out, then open the answer.

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Answer: 314

  1. τ=NIπr2Bsin⁡θ\tau = NI\pi r^2 B\sin\theta
  2. τ=125×1×3.14×(0.02)2×0.4×sin⁡30∘\tau = 125 \times 1 \times 3.14 \times (0.02)^2 \times 0.4 \times \sin30^\circ
  3. τ=0.157×0.4×0.5=3.14×10−2=314×10−4 N m\tau = 0.157 \times 0.4 \times 0.5 = 3.14\times10^{-2} = 314\times10^{-4}\text{ N m}
  4. So α=314\alpha = 314.
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