JEE Mains · Physics · STD 12 - 5. Magnetism and matter
A bar magnet with a magnetic moment \(5.0\,Am ^2\) is placed in parallel position relative to a magnetic field of \(0.4\,T\). The amount of required work done in turning the magnet form parallel to antiparallel position relative to the field direction is \(.........\,J\)
- A \(4\)
- B \(1\)
- C \(2\)
- D \(0\)
Answer & Solution
Correct Answer
(A) \(4\)
Step-by-step Solution
Detailed explanation
\(u =- MB \cos \theta\) \(W =\Delta u\) \(W =- MB \cos 180^{\circ}\left(- mB \cos 0^{\circ}\right)\) \(W =2 MB =2 \times 5 \times 0.4=4\,J\)
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