A bar magnet is divided into two pieces, which of the following statement is correct?

Analyze the question

You are asked what happens when a bar magnet is cut into two pieces. This tests your knowledge of magnetic poles and domains.

Concept

Magnetic poles always exist in pairs (north and south). You cannot isolate a single pole, because there are no magnetic monopoles. A magnet is made of many tiny magnetic domains, all aligned in the same direction. Cutting the magnet does not destroy this alignment.

Solution

1. Start with one bar magnet with a N pole at one end and a S pole at the other.
2. Cut it in the middle. The cut ends do not become "bare" poles. Each piece develops its own N and S poles. The piece that had the N end gets a new S pole at the cut, and the piece that had the S end gets a new N pole at the cut.
3. The result is two complete bar magnets. Each is weaker than the original, since each has fewer aligned domains.

Checking the options

• A. Two new magnets are created. ✔ Correct. Each piece has its own N and S poles.
• B. Each piece becomes stronger. ✘ Wrong. Each piece is weaker than the original, not stronger.
• C. An electric field is created. ✘ Wrong. Cutting a magnet does not produce an electric field. That needs a changing magnetic field or a charge.
• D. The magnet is demagnetized. ✘ Wrong. Both pieces stay magnetized, because the domains remain aligned.

Answer: A. Two new magnets are created.

Exam tip: Remember "break a magnet, get more magnets." No matter how many times you cut it, every piece has both a N and a S pole. This also supports the fact that magnetic monopoles do not exist, which JAMB likes to test.