Practice question

**Circular loop deformed into straight wire** in field B=0.12 T radius 16 cm area πr²=0.0804 m² flux 0.00965 Wb drops to zero in 0.6 s e=0.0161 V, illustrating flux change due to area change induces emf, even without B change, area deformation changes Φ = B A cosθ. Initial flux: Φ = B A = 0.25 × π × (0.09)² = 0.00636 Wb . Final flux = 0. ε = (Δ Φ/Δ t) = (0.00636/0.4) = 0.0159 V ≈ 0.016 V . Using Φ = B A cosθ, e = -N dΦ/dt = -N A dB/dt = B l v = N B A ω