JEE Main 2024 Physics question
A circular coil having 200 turns, 2.5 × 10⁻⁴ m² area and carrying 100 A current is placed in a uniform magnetic field of 1 T. Initially the magnetic dipole moment was directed along . Amount of work, required to rotate the coil through 90° from its initial orientation such that becomes perpendicular to , is J.
Answer: 5
Solution
M = NIA = 200 × 100 × 2.5 × 10⁻⁴ = 5 A m²; W = MB(1 − cos 90°) = 5 J.