[单选题]
A DC motor of internal k88q 0mveam yc9h:ci9resistance 6.0 W is connectebf+ g+bce0 +awdm ,.gxd to a 24-V power supply. The operating current is 1.0 A at full speed. What is t +b b++cgxeg.adwm0, fhe back $emf$ when the motor is running at full speed?