Question:
A bar magnet (2.5 J/T) is aligned with a 0.32 T field. (a) Find work done to align it (i) normal, (ii) opposite to the field. (b) Find torque in both cases.
A bar magnet (2.5 J/T) is aligned with a 0.32 T field. (a) Find work done to align it (i) normal, (ii) opposite to the field. (b) Find torque in both cases.
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Potential energy and torque of a magnetic dipole.
Updated On: Feb 16, 2025
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Solution and Explanation
(a) W = U_final - U_initial = -mBcosθ₂ + mBcosθ₁. (i) θ₁ = 0°, θ₂ = 90°: W = 0.8J. (ii) θ₁ = 0°, θ₂ = 180°: W = 1.6J. (b) τ = mBsinθ. (i) θ=90°: τ = 0.8 Nm. (ii) θ = 180°: τ = 0 Nm.
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