PX157 - D1a - faraday's law

faraday's law of induction statues that the induced emf in a closed loop equals minus the rate of change of magnetic flux though the loop:

ϵ = - \frac{d ϕ_{B}}{d t}

where, magnetic flux, $ϕ_{B} = \iint_{S} \vec{B} \cdot d \vec{S}$

ϵ = - N \frac{d ϕ_{B}}{d t}