GEOLOGY

Detailed explanation-1: -Assertion :Iron, cobalt, nickel and CrO2 are called ferromagnetic substances.

Detailed explanation-2: -Iron and nickel are two of the most well-known ferromagnets, that is, conducting materials with a permanent magnetization1.

Detailed explanation-3: -Iron, nickel, cobalt and some of the rare earths (gadolinium, dysprosium) exhibit a unique magnetic behavior which is called ferromagnetism because iron (ferrum in Latin) is the most common and most dramatic example.

Detailed explanation-4: -Since then only three elements on the periodic table have been found to be ferromagnetic at room temperature-iron (Fe), cobalt (Co), and nickel (Ni).

Detailed explanation-5: -Only ferromagnetic materials such as iron, cobalt, and nickel are attracted to magnetic fields strong enough to be truly considered magnetic. However, all metals can be placed into one of three categories: Ferromagnetic.