Steel is not used for the core of an electromagnet that must be switched off because steel:

  1. cannot be magnetised
  2. keeps its magnetism (becomes a permanent magnet)
  3. is too light
  4. is non-metallic
Answer

B) keeps its magnetism (becomes a permanent magnet)

Hard magnetic material. SLO P-09-E-36 · Knowledge

Physics MCQ · More Magnetism and Electromagnetic Induction MCQs · Practise