Question

What does negative EMF mean?

Answer 1

Faraday' Law of Induction:

1. Whenever a conductor is placed in a varying magnetic field, an electromotive force is induced. If the conductor circuit is closed, a current is induced, which is called induced current.
2. The induced emf in a coil is equal to the rate of change of flux linkage.
3. $\begin{array}{l}\epsilon =-N\frac{\mathrm{\Delta }\varphi }{\mathrm{\Delta }t}\end{array}$Where ε is the electromotive force, Φ is the magnetic flux, and N is the number of turns.
4. The negative sign implies that the electromotive force induced will be induced in order to oppose the cause.
5. According to Lenz's law, suppose the emf is induced by a magnetic field increases in the $-\mathrm{z}$ direction, the emf will be induced to produce a magnetic field in the $+\mathrm{z}$ direction
6. The electric potential produced by either an electrochemical cell or by changing the magnetic field is known as emf or electromotive force.

Hence, a negative sign in EMF shows the direction of induced EMF is opposite to the original.