# Faraday's induced emf equation

cblair
Forum Coordinator

Why is there negative sign in Faraday’s induced emf equation?

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cblair
Forum Coordinator

Why is there negative sign in Faraday’s induced emf equation?

Tagged:

## Comments

"Faraday’s laws of electromagnetic induction states that when a coil of wire is placed in a changing magnetic field (B) an EMF (E) is induced in the coil and the induced EMF is proportional to the rate of change of flux linkage with the coil (dφ/dt).

E = N(- dφ/dt)

Meaning of the minus sign in Faraday’s law is explained by Lenz’s law which says if the B field changes, the voltage induced in the coil will try to drive a current that produces a B-field which opposes the change(in primary B field)."

Thanks, Could you please elaborate more on what does the negative sign signify?