(N/A) When an electric current flows through a solenoid (coil),it behaves like a bar magnet. One face of the coil acts as a North $(N)$ pole,while the opposite face acts as a South $(S)$ pole.
The polarity of the ends can be determined using the following rule:
$(1)$ If the current,when viewed from one end of the coil,appears to flow in a clockwise direction,that face behaves as a South $(S)$ pole.
$(2)$ If the current,when viewed from one end of the coil,appears to flow in an anticlockwise direction,that face behaves as a North $(N)$ pole.
This is illustrated in the provided figure,where the clockwise current corresponds to the South pole and the anticlockwise current corresponds to the North pole.