What is back emf?

What is back emf? 
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1 Answer

Answer :

Back EMF: When a current carrying conductor is placed in a magnetic field it experiences a force; when it moves due to the force it (conductor) cuts the magnetic field due to which an emf is induced in it. According to Lenz’s law the effect of induced emf is to oppose the cause of it. The armature current (hence the applied armature voltage) is opposed by the induced emf which is therefore called as Back emf.
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