A 250 -Turn rectangular coil of length 2.1 cm and width 1.25 cm carries a current of 85 μA and subjected to a magnetic field of strength 0.85 T . Work - Physics MCQ NEET 2017 2026 | ExamTest.live

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A 250 -Turn rectangular coil of length 2.1 cm and width 1.25 cm carries a current of 85 μ A and subjected to a magnetic field of strength 0.85 T . Work done for rotating the coil by 18 0^{\circ} against the torque is:

Solution & Step-by-step Explanation

Work done W = MB (cos θ_{1} - cos θ_{2}) .Magnetic moment M = N I A = 250 \times (85 \times 1 0^{- 6}) \times (2.1 \times 1.25 \times 1 0^{- 4}) .Initial angle θ_{1} = 0^{\circ}, Final angle θ_{2} = 18 0^{\circ} . W = MB (1 - (- 1)) = 2 MB . W = 2 \times [250 \times 85 \times 1 0^{- 6} \times 2.625 \times 1 0^{- 4}] \times 0.85 . W \approx 9.1 \times 1 0^{- 6} J = 9.1 μ J .

Try it yourself before checking the explanation above.

A 250 -Turn rectangular coil of length 2.1 cm and width 1.25 cm carries a current of 85 μ A and subjected to a magnetic field of strength 0.85 T . Work done for rotating the coil by 18 0^{\circ} against the torque is:

9.1 μ J

4.55 μ J

2.3 μ J

1.15 μ J

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