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Electromagnetic Induction — JEE physics STD 12 Science — Question

CBSE BoardEnglish MediumSTD 12 ScienceJEE physicsElectromagnetic Induction1 Mark
Question
Assertion : An electric motor will maximum efficient when back e.m.f. is equal to applied e.m.f.
Reason : Efficiency of electric motor is depends only on magnitude of back e.m.f.
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Answer

(d) Efficiency of electric motor is maximum when the back emf set up in the armature is half the value of the applied battery emf.

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