emf

Back EMF

Back EMF is the voltage generated by a motor that opposes the voltage supplied to it.

Back EMF is the EMF caused by Electromagnetic Induction.

$V=RI+k_{e}w$

https://www.quora.com/What-is-the-difference-between-back-EMF-generated-EMF-and-induced-EMF-as-far-as-motors-and-generators-are-concerned