Which of the following is a property of steel?

1. Analyze the question The question asks about the magnetic property of steel, specifically how it compares with soft iron.

2. Explain the concept Magnetic materials fall into two groups:

• Soft magnetic materials (e.g., soft iron): They are easily magnetized and easily demagnetized. They lose their magnetism quickly, so they are used for temporary magnets, such as electromagnets, transformer cores, and relay cores.
• Hard magnetic materials (e.g., steel): They are harder to magnetize, but once magnetized they retain their magnetism for a long time. They are used for permanent magnets, such as compass needles and loudspeaker magnets.

The difference comes from the structure of the material. In steel (iron with carbon), the magnetic domains are "locked" in place, so they resist both aligning and misaligning.

3. Solution: check each option

• A. It cannot retain its magnetism longer than iron. False. Steel retains magnetism longer than soft iron.
• B. It can be used for making temporary magnets. False. This describes soft iron.
• C. It can be used for making permanent magnets. True. Steel keeps its magnetism, so it suits permanent magnets.
• D. It can easily be magnetized and demagnetized. False. This describes soft iron. Steel is difficult to magnetize and to demagnetize.

4. Answer Option C: steel can be used for making permanent magnets.

5. Exam tip Remember the pairing: Soft iron = Temporary (easy on, easy off) and Steel = Permanent (hard on, stays on). In JAMB, "steel" usually points to "permanent magnet" and "soft iron" to "electromagnet/temporary magnet."