Select all that are true. Group of answer choices in a dc motor, induced or back emf results from magnetic force exerted by stator on the charges in the rotor. Back emf is the useful energy output as a result of the interaction between the rotor and the stator of a motor. A dc motor draws a current i. The internal resistance of the motor is r. If v is the voltage applied at the terminals of the motor, back emf epsilon is the difference of v and i r. A dc generator has the same major parts as a dc motor, i. E. Stator, rotor, commutator, and brushes. A dc generator converts mechanical energy into electrical energy; whereas a dc motor converts electrical energy into mechanical energy. The purpose of brushes in a dc motor or generator is to keep the commutator clean of any dirt or foreign objects.