Number of turns, N=45 Radius, r=4cm=0.04m Change in magnetic field, ∆B=0.70T−0=0.70T Time interval, ∆t=220s The plane of the coil is perpendicular to the magnetic field, so flux is maximum. Step 1: Rate of change of magnetic field ‌
dB
dt
=‌
0.70
220
=3.18×10−3T∕s Step 2: Area of the coil A=πr2=π(0.04)2=π×1.6×10−3=5.027×10−3m2 Step 3: Induced emf (Faraday's law) ε=NA‌