A conducting circular loop is in a uniform magnetic field of 0.4 T perpendicular to its plane. Its radius increases at a constant rate 1 mm s⁻¹. When the radius is 2 cm, the induced emf i s ______ μV.

Question

G1 Physics · Accepted Answer

Magnetic flux: Φ = BA = Bπr² Thus, |ε| = |dΦ/dt| = B·2πr·dr/dt Given: B = 0.4 T r = 2 cm = 2×10⁻² m dr/dt = 1 mm s⁻¹ = 10⁻³ m s⁻¹ |ε| = 0.4×2π×2×10⁻²×10⁻³ ≈ 50.3×10⁻⁶ V ≈ 50 μV Final value: 50