Magnetic Flux and Faraday's Laws

Cue	Notes
Magnetic Flux	Φ = BA cos θ; maximum when B ⊥ surface (θ = 0); [M $L^{2}$ $T^{-2}$ $A^{-1}$ ]; unit: Weber (Wb)
Faraday 1st	Changing Φ → induced EMF (qualitative)
Faraday 2nd	EMF = −dΦ/dt (quantitative); [EMF] = [M $L^{2}$ $T^{-3}$ $A^{-1}$ ]; unit: V
Negative Sign	This IS Lenz's law embedded in the formula
N-turn coil	EMF = −N(dΦ/dt) = −d(NΦ)/dt where NΦ = flux linkage
Rate matters	EMF depends on dΦ/dt, NOT on Φ itself

Summary

Flux measures how much B penetrates a surface. Only the RATE of change of flux induces EMF—constant flux (even large) induces nothing. For N turns, multiply by N. Unit analysis: [Wb/s] = [V] confirms the formula.