Answer: iron.
- A iron
- B copper
- C bismuth
- D water
Correct answer: A. iron
Explanation: Iron (also cobalt and nickel) is ferromagnetic; copper and bismuth are diamagnetic.
Magnetic field of a bar magnet: field lines emerge from the north pole and re-enter at the south pole outside the magnet, forming continuous closed loops. Image: Geek3, CC BY-SA 3.0, via Wikimedia Commons.
Concept context
Bar magnets, Earth's magnetism, and how different materials respond to an external magnetic field - diamagnetic, paramagnetic, and ferromagnetic behaviour.