[单选题]
A DC motor of internal resistance 6.0 W is conneccyun4 /(w0 *gjxuad0tted to a 243h gpuj cy-2pesvnmffq)6)b9;4jzm 8-V power supply. The operating currevnqh42e6m9z fpbj fu))38c msj-g p;ynt is 1.0 A at full speed. What is the back $emf$ when the motor is running at full speed?
