A coil of 150 turns and area 0.06 m² is in a 0.14 T field that drops to zero in 0.3 s. What is the induced emf?
**Field decreasing to zero** induces emf trying to maintain field, current direction such that its field adds to original. For 150 turns area 0.06 m² B 0.14 T to zero in 0.3 s, e=150×0.06×0.14/0.3=4.2 V, as earlier, showing linear dependence on N, A, ΔB/Δt. Δ Φ = B A = 0.14 × 0.06 = 0.0084 Wb . ε = N (Δ Φ/Δ t) = 150 × (0.0084/0.3) = 150 × 0.028 = 4.2 V . Using Φ = B A cosθ, e = -N dΦ/dt = -N A dB/dt = B l v = N B A ω sinωt, L = μ₀ N²A/l, M =
Ref: NCERT > Physics Book > Electromagnetic Induction > Induced EMF Due to Change in Magnetic Field