[单选题]
A DC motor of interna0 xs lo34nxuum6d/zi. f5gyj8l resis ,g20mx-z)hjatt7p3kvn i(ewaa5qk + tance 6.0 W is connected to a 24-V power supply. The operating current is 1.0 A mavait73kkpzjtx 5 h)e, g0w-+n (aq 2at full speed. What is the back $emf$ when the motor is running at full speed?