Question

Which of the following is a ferromagnetic substance?

(a) Cobalt

(b) Nitrogen

(c) Nitric oxide

(d) Helium

This question was posed to me during an interview for a job.

This intriguing question comes from Instrumentation and Control in chapter Instrumentation and Control of Fermentation Technology

Answer 1

Right option is (a) Cobalt

The best I can explain: Cobalt, Iron are examples of a ferromagnetic substance. The electrons aligned themselves in the direction of the magnetic field and are strongly magnetized. Here, Nitrogen is a diamagnetic material and Nitric oxide is a paramagnetic material.