Electromotive Force (emf)

Electromotive force (EMF) is equal to the terminal potential difference when no current flow.

→ Often referred to for Battery

$\mathcal{E}=-\frac{d{\Phi }_m}{dt}=-\frac{d}{dt}{\int }_S\vec{B}\cdot d\vec{S}$

Two types of EMF

• Transformer (Device) EMF
  • The magnetic field changes with time.
• Motional EMF
  • Magnetic flux changes with time due to motion of the loop

Related

• Electromagnetic Induction
• Induced emf