An Electric Motor Draws a Current of 2

Multiple Choice

An electric motor draws a current of 2.60 A from a 18.0-V battery when it runs at normal speed.If the motor's armature is "jammed" so that it cannot rotate,the current suddenly rises to 10.0 A.What is the back emf of the motor when running at normal speed?

A) 4.68 V
B) 10.0 V
C) 22.7 V
D) 13.3 V
E) 133 V