Magnetic Field and Earth's Magnetism — Flashcards

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Magnetic dipole moment of a current loop: m = IA, where I is current in ampere and A is area in square metre. Vector form: m→ = IA→. For N turns: m→ = NIA→. Unit: A-m². Dimensions: [AL²]. Quick check:…

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Given: I = 3 A, A = 0.2 m² Formula: m = IA Substitution: m = 3 A × 0.2 m² Calculation: m = 0.6 A-m² Answer: 0.6 A-m² Unit is correct because current loop magnetic moment is measured in A-m².

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A current loop produces a magnetic field and has north-like and south-like behaviour. In a magnetic field, it experiences torque and tends to align its axis parallel to the field, just like a bar magn…

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Given: N = 40, I = 0.5 A, A = 0.03 m² Formula: m = NIA Substitution: m = 40 × 0.5 × 0.03 Step 1: 40 × 0.5 = 20 Step 2: 20 × 0.03 = 0.6 Answer: m = 0.6 A-m²…

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Torque on a magnetic dipole: τ = mB sinθ Vector form: τ→ = m→ × B→ Meaning: m is magnetic dipole moment, B is magnetic field, and θ is the angle between them. Maximum torque: τmax = mB when θ = 90°. I…

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Given: m = 2 A-m², B = 0.4 T, θ = 30° Formula: τ = mB sinθ Substitution: τ = 2 × 0.4 × sin30° Use sin30° = 0.5 Calculation: τ = 0.8 × 0.5 = 0.4 N-m Answer: 0.4 N-m…

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Torque is given by τ = mB sinθ. The sine value is maximum at θ = 90°, where sin90° = 1. So the torque becomes τmax = mB. Physically, the field tries to turn the dipole to align it with the field, and …

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Given: m = 1.5 A-m², B = 0.22 T For θ = 0°: U0 = -mB For θ = 90°: U90 = 0 Work required: W = U90 - U0 = 0 - (-mB) = mB Substitution: W = 1.5 × 0.22 Calculation: W = 0.33 J Answer: 0.33 J…