Which of the following describes alternating current?
Current that alternates between a positive direction and zero
Current that alternates between a negative direction and zero
Current that alternates between positive and negative directions✓الإجابة الصحيحة
All these answers are correct
الشرح
Alternating current periodically reverses direction, flowing first one way through the circuit and then the other. A current that only varies between one polarity and zero is pulsating direct current, which is why the first two choices do not describe AC.