Assertion : An electric motor will have maximum efficiency when back emf becomes equal to half of applied emf.
Reason : Efficiency of electric motor depends only on magnitude of back emf.

Assertoion : An electric motor will have maximum efficiency when back emf becomes equal of half of applied emf. Reason. Power factor of series R_L circuit is given by cos theta = (2R)/(sqrt(R^(2) + omega^(2) L^(2)))

In a dc motor, induced e.m.f. will be maximum

In the above question, show that power output of electri motor is maximum when the back emf is one-half of the sourece emf, provided the resistance of the winding of the motor is negligible .

(a) An electric motor runs on a d.c. source of emf e and internal resistance r. show that the power output of the source is maximum when the current drawns by the motor is epsilon//2r . (b) Show that power output of electric motor is maximum when the back emf is one-half the source emf provided the resistance of the windings of the motor is negligible. (c) Compare and contrast carefully the situation in this excercise with that in Example 43 above.

(a) An electric motor runs on a d.c. source of emf e and internal resistance r. show that the power output of the source is maximum when the current drawns by the motor is epsilon//2r . (b) Show that power output of electric motor is maximum when the back emf is one-half the source emf provided the resistance of the windings of the motor is negligible. (c) Compare and contrast carefully the situation in this excercise with that in Example 43 above.

An electric motor operates with an efficiency of 90% . A pump operated by the motor has an efficiency of 80% . The overall efficiency of the system is

Assertion : An electric motor converts electical energy to mechanical energy. Reason : The working of the motor is based on mutualn induction.