Faraday’s law: ( \mathcal{E} = -N \frac{\Delta \Phi}{\Delta t} ) (\Delta \Phi = 0.01 - 0.05 = -0.04 , \text{Wb}) (\frac{\Delta \Phi}{\Delta t} = \frac{-0.04}{0.2} = -0.2 , \text{Wb/s}) ( \mathcal{E} = -200 \times (-0.2) = 40 , \text{V} ) (magnitude: 40 V)
