[Physics] How to find the polarity of a U-shaped electromagnet

electricityelectromagnetism

How do I find the polarity of a U-shaped electromagnet ?

U shaped solenoid

Current flowing clockwise –> South Pole

Current flowing anticlockwise –> North Pole

However the direction of flow of current changes when seen from top as compared to bottom. From the examples, I find that one should view the direction from the bottom. So why is this so ?

In this image:

Another solenoid

I believe the polarity at P is North and that at Q is South. Am I right ?

Is there any other method to determine the polarity of a U-shaped electromagnet ?

Best Answer

The current direction $I$ is from the positive terminal of the voltage source to the negative terminal.

enter image description here

Look end on along the axis of the electromagnet.
Clockwise current $I$ direction $\Rightarrow$ south pole
Anticlockwise current $I$ direction $\Rightarrow$ north pole