Electromagnetism is a part of physics that studies the interaction between electricity and magnetism.

He is an expert in toxicology and conducts many studies.

He has a deep interest in astronomy.

He is an expert in rhetoric, teaching the techniques of speech.

He is globally recognized as an expert in Indology.

He is an expert in gemology, and he is good at evaluating the quality of diamonds.

He is known as an expert in gerontology.

Semiotics is the study of signs and symbols used in society and culture.

He is an expert in crystallography.

He is majoring in humanities at university.