Practice question

Given: The magnetic potential energy of a dipole with m = 0.4 A m² in a field B = 0.7 T at 180° is: These values define the system as per NCERT data. Formula: U_m = -m B cosθ. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Given: m = 0.4 A m², B = 0.7 T, θ = 180°, cos 180° = -1 . Substitute: U_m = -0.4 × 0.7 × (-1) = 0.28 J . Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.