The substance that is not magnetic is typically something like wood, plastic, glass, or brass, while iron, nickel, and cobalt are magnetic materials that are strongly attracted to magnets.

In the most common multiple-choice questions for “which of the following is not a magnetic substance,” the non-magnetic options are usually:

  • Wood (clearly non-magnetic).
  • Brass, an alloy of copper and zinc, which is non-magnetic.
  • Other non-magnetic metals such as aluminum, copper, tin, and lead.

By contrast, these are magnetic (ferromagnetic) substances:

  • Iron
  • Nickel
  • Cobalt
  • Many steels (like ordinary iron–steel).

So, if your options look like:

  • Iron
  • Nickel
  • Cobalt
  • Wood

→ The correct answer is wood , as it is not a magnetic substance.

If the options are:

  • Iron
  • Nickel
  • Cobalt
  • Brass

→ The correct answer is brass , which is non-magnetic.

Always pick the one that is a non-metal (like wood) or a clearly listed non- magnetic metal (like brass, aluminum, or copper) when answering “which of the following is not a magnetic substance.”

Information gathered from public forums or data available on the internet and portrayed here.