But we do not know whether the force is pushing or pulling (the same direction (both forces are parallel) but: .........[ ]<-F-- or .......[ ]--F-->). I suppose the correct answer is B
Answer:
U = – 0.12J
Explanation:
Given N = 10 turns, I = 5A, r = 5×10-²m
B^ = 0.05 T iˆ+ 0.3 T kˆ
Magnitude of the magnetic field vector B = √(0.05²+0.3²) = 0.304T
Area = πr² = π(5×10-²)² = 7.85×10-³m²
Magnetic moment μ = NIA
μ = 10×5×7.85×10-³ = 0.3925Am²
U = -μ•B = –0.3925×0.304 = –0.12J
The sign is negative because the magnetic moment is aligned with the magnetic field.
