Are there magnets with a single magnetic pole? Is it possible for the pole strength to be different for the north and south poles of the same bar magnet?
No, there are no magnets with a single magnetic pole. According to the laws of magnetism, every magnet has both a north and a south pole. When a magnet is broken into smaller pieces, each piece will still have a north and a south pole.
As for the second part of your question, the pole strength of a magnet is generally the same for both the north and south poles of the same magnet. Magnets are generally manufactured to have similar strengths on both poles. However, it is possible to create magnets where the north and south poles have different strengths, although this is not common in everyday magnets.
To determine if the pole strength of a magnet is different for its north and south poles, you can use a magnetic compass. Place the compass near each pole of the magnet and observe if the needle points in the same or opposite direction. If the needle is deflected in different ways near the north and south poles, it suggests a difference in pole strength. However, it's important to note that most commercial magnets have similar strengths on both poles.