A coil of 50 turns and area 0.06 m² is in a 0.15 T field that drops to zero in 0.3 s. What is the induced emf?
**Induced emf due to B change** e = -N A dB/dt, N turns, A area (m²), dB/dt rate of change of field (T/s). For 110 turns area 0.035 m² B 0.09 T to 0 in 0.5 s, dB/dt=0.18 T/s, e=110×0.035×0.18=0.693 V, direction opposes decrease via Lenz's law. Δ Φ = B A = 0.15 × 0.06 = 0.009 Wb . ε = N (Δ Φ/Δ t) = 50 × (0.009/0.3) = 50 × 0.03 = 1.5 V . Using Φ = B A cosθ, e = -N dΦ/dt = -N A dB/dt = B l v = N B A ω sinωt, L = μ₀
Ref: NCERT > Physics Book > Electromagnetic Induction > Induced EMF Due to Change in Magnetic Field
