JEE Mains · Physics · STD 12 - 4. Moving charges and magnetism
A circular coil having \(200\) turns, \(2.5 \times 10^{-4} \mathrm{~m}^2\) area and carrying \(100 \mu \mathrm{A}\) current is placed in a uniform magnetic field of \(1 \mathrm{~T}\). Initially the magnetic dipole moment \((\vec{M})\) was directed along \(\vec{B}\). Amount of work, required to rotate the coil through \(90^{\circ}\) from its initial orientation such that \(\overrightarrow{\mathrm{M}}\) becomes perpendicular to \(\vec{B}\) is _______ \(\mu \mathrm{J}\).
- A \(8\)
- B \(3\)
- C \(4\)
- D \(5\)
Answer & Solution
Correct Answer
(D) \(5\)
Step-by-step Solution
Detailed explanation
We know \(\mathrm{W}_{\text {ext }} =\Delta \mathrm{U}+\Delta \mathrm{KE} \quad(\mathrm{P} . \mathrm{E} .=-\overrightarrow{\mathrm{M}} \cdot \overrightarrow{\mathrm{B}})\)…
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