Where are a current-carrying solenoid's magnetic poles?
A solenoid has a north pole at one end. But which end? Wind a coil and switch the current on, and the answer is already fixed by which way the current circulates around the turns.
Look straight at one face of a flat coil carrying a current. The current circulates around the face: clockwise or counterclockwise, as you see it.
Your right hand again settles it. Curl your right-hand fingers the way the current circulates. Your thumb points out of the coil's north face. This is the grip rule for a coil.
Looking at the near face of a coil, the current circulates clockwise. Which pole is the near face?
Match the curl:
Curl your right-hand fingers clockwise, with the current.
Read the thumb:
Your thumb points away from you, so the north face is the far face.
The near face is a south pole.
The face of a coil toward you is a north pole. Which way does the current circulate, as you see it?
Set the thumb:
Point your right thumb toward yourself, out of the north face.
Read the curl:
Your fingers curl counterclockwise.
The current circulates counterclockwise, as you see it.
Here are six fast reads. Use your right hand every time.
You face a coil. Its current circulates counterclockwise. Which pole faces you?
You face a coil. Its current circulates clockwise. Which pole faces you?
Seen from above, a flat coil's current runs clockwise. Which pole is its top face?
A coil's face toward you is a north pole. Which way does its current circulate?
A coil's face toward you is a south pole. Which way does its current circulate?
The near face of a coil is a north pole. What is its far face?
Looking at the near face of a coil, the current runs counterclockwise. A bar magnet's north pole is brought toward that face. What happens?
The top face of a flat coil on a bench is a north pole. Which way does the current circulate?
The current in a coil is reversed. What happens to the coil's north face?